diff --git a/ProcessMaker/Traits/TaskControllerIndexMethods.php b/ProcessMaker/Traits/TaskControllerIndexMethods.php
index aba096c360..2ad7b59031 100644
--- a/ProcessMaker/Traits/TaskControllerIndexMethods.php
+++ b/ProcessMaker/Traits/TaskControllerIndexMethods.php
@@ -6,6 +6,7 @@
 use Illuminate\Database\QueryException;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\DB;
 use ProcessMaker\Filters\Filter;
 use ProcessMaker\Managers\DataManager;
 use ProcessMaker\Models\Process;
@@ -69,7 +70,7 @@ private function applyFilters($query, $request)
         }
 
         $filterByFields = [
-            'process_id',
+            'process_request_tokens.process_id' => 'process_id',
             'process_request_tokens.user_id' => 'user_id',
             'process_request_tokens.status' => 'status',
             'element_id',
@@ -247,60 +248,6 @@ private function applyColumnOrdering($query, $request)
             'is_priority',
         ];
 
-        $hasProcessRequestOrdering = false;
-        $hasUserOrdering = false;
-        foreach ($orderColumns as $column) {
-            $normalizedColumn = preg_replace(
-                '/^(process_request|processRequests)\./',
-                'process_requests.',
-                $column
-            );
-
-            if (in_array($normalizedColumn, array_map(
-                fn ($name) => 'process_requests.' . $name,
-                $processRequestColumns
-            ), true) || preg_match('/^data\.[A-Za-z0-9_-]+(?:\.[A-Za-z0-9_-]+)*$/', $column)) {
-                $hasProcessRequestOrdering = true;
-            }
-            if ($column === 'user.name') {
-                $hasUserOrdering = true;
-            }
-        }
-
-        if ($hasProcessRequestOrdering) {
-            $query->leftJoin(
-                'process_requests',
-                'process_requests.id',
-                '=',
-                'process_request_tokens.process_request_id'
-            );
-        }
-        if ($hasUserOrdering) {
-            $query->leftJoin(
-                'users',
-                'users.id',
-                '=',
-                'process_request_tokens.user_id'
-            );
-        }
-        if ($hasProcessRequestOrdering || $hasUserOrdering) {
-            if ($query->getQuery()->columns === null) {
-                $query->select('process_request_tokens.*');
-            } else {
-                $query->select(array_map(function ($column) {
-                    if (!is_string($column)) {
-                        return $column;
-                    }
-
-                    $column = ltrim($column, '.');
-
-                    return str_contains($column, '.')
-                        ? $column
-                        : 'process_request_tokens.' . $column;
-                }, $query->getQuery()->columns));
-            }
-        }
-
         $hasValidOrdering = false;
         foreach ($orderColumns as $index => $column) {
             $direction = strtolower($orderDirections[$index] ?? $orderDirections[0] ?? 'asc');
@@ -312,17 +259,44 @@ private function applyColumnOrdering($query, $request)
             );
 
             if ($column === 'user.name') {
-                $query->orderBy('users.firstname', $direction)
-                    ->orderBy('users.lastname', $direction);
+                $query->orderBy(
+                    $this->relatedOrderSubquery('users', 'firstname', 'users.id', 'process_request_tokens.user_id'),
+                    $direction
+                )->orderBy(
+                    $this->relatedOrderSubquery('users', 'lastname', 'users.id', 'process_request_tokens.user_id'),
+                    $direction
+                );
                 $hasValidOrdering = true;
             } elseif (preg_match('/^data\.([A-Za-z0-9_-]+(?:\.[A-Za-z0-9_-]+)*)$/', $column, $matches)) {
-                $query->orderBy('process_requests.data->' . str_replace('.', '->', $matches[1]), $direction);
+                $jsonColumn = 'data->' . str_replace('.', '->', $matches[1]);
+                $query->orderBy(
+                    $this->relatedOrderSubquery(
+                        'process_requests',
+                        $jsonColumn,
+                        'process_requests.id',
+                        'process_request_tokens.process_request_id'
+                    ),
+                    $direction
+                );
                 $hasValidOrdering = true;
             } elseif (in_array($normalizedColumn, array_map(
                 fn ($name) => 'process_requests.' . $name,
                 $processRequestColumns
             ), true)) {
-                $query->orderBy($normalizedColumn, $direction);
+                $columnName = substr($normalizedColumn, strlen('process_requests.'));
+                if ($columnName === 'id') {
+                    $query->orderBy('process_request_tokens.process_request_id', $direction);
+                } else {
+                    $query->orderBy(
+                        $this->relatedOrderSubquery(
+                            'process_requests',
+                            $columnName,
+                            'process_requests.id',
+                            'process_request_tokens.process_request_id'
+                        ),
+                        $direction
+                    );
+                }
                 $hasValidOrdering = true;
             } elseif (in_array($column, $tokenColumns, true)) {
                 $query->orderBy('process_request_tokens.' . $column, $direction);
@@ -335,6 +309,14 @@ private function applyColumnOrdering($query, $request)
         }
     }
 
+    private function relatedOrderSubquery(string $table, string $column, string $localKey, string $foreignKey)
+    {
+        return DB::table($table)
+            ->select($column)
+            ->whereColumn($localKey, $foreignKey)
+            ->limit(1);
+    }
+
     private function applyStatusFilter($query, $request)
     {
         $statusFilter = $request->input('statusfilter', '');
@@ -342,7 +324,7 @@ private function applyStatusFilter($query, $request)
             $statusFilter = array_map(function ($value) {
                 return mb_strtoupper(trim($value));
             }, explode(',', $statusFilter));
-            $query->whereIn('status', $statusFilter);
+            $query->whereIn('process_request_tokens.status', $statusFilter);
         }
     }
 
@@ -544,8 +526,8 @@ private function applyForCurrentUser($query, $user)
         }
 
         $query->where(function ($query) use ($user) {
-            $query->where('user_id', $user->id)
-                ->orWhereIn('id', $user->availableSelfServiceTasksQuery());
+            $query->where('process_request_tokens.user_id', $user->id)
+                ->orWhereIn('process_request_tokens.id', $user->availableSelfServiceTasksQuery());
         });
     }
 
diff --git a/tests/Feature/Api/TaskListNonAdminCaseTitleOrderTest.php b/tests/Feature/Api/TaskListNonAdminCaseTitleOrderTest.php
new file mode 100644
index 0000000000..0093076420
--- /dev/null
+++ b/tests/Feature/Api/TaskListNonAdminCaseTitleOrderTest.php
@@ -0,0 +1,193 @@
+<?php
+
+namespace Tests\Feature\Api;
+
+use PHPUnit\Framework\Attributes\Group as TestGroup;
+use ProcessMaker\Models\ProcessRequest;
+use ProcessMaker\Models\ProcessRequestToken;
+use ProcessMaker\Models\User;
+use Tests\Feature\Shared\RequestHelper;
+use Tests\TestCase;
+
+/**
+ * Regression for tasks index 1052 (ambiguous user_id) when a non-admin
+ * lists tasks ordered by process_requests.case_title.
+ */
+#[TestGroup('process_tests')]
+class TaskListNonAdminCaseTitleOrderTest extends TestCase
+{
+    use RequestHelper;
+
+    public function testNonAdminCanListTasksOrderedByCaseTitleDesc()
+    {
+        $this->user = User::factory()->create([
+            'is_administrator' => false,
+            'status' => 'ACTIVE',
+        ]);
+        $otherUser = User::factory()->create([
+            'is_administrator' => false,
+            'status' => 'ACTIVE',
+        ]);
+
+        $zetaRequest = ProcessRequest::factory()->create();
+        $alphaRequest = ProcessRequest::factory()->create();
+        $otherRequest = ProcessRequest::factory()->create();
+        $zetaRequest->forceFill(['case_title' => 'Zeta mandate'])->saveQuietly();
+        $alphaRequest->forceFill(['case_title' => 'Alpha mandate'])->saveQuietly();
+        $otherRequest->forceFill(['case_title' => 'Omega mandate'])->saveQuietly();
+
+        $zetaTask = ProcessRequestToken::factory()->create([
+            'user_id' => $this->user->id,
+            'process_id' => $zetaRequest->process_id,
+            'process_request_id' => $zetaRequest->id,
+            'element_type' => 'task',
+            'status' => 'ACTIVE',
+            'is_self_service' => false,
+            'is_priority' => true,
+            'completed_at' => null,
+        ]);
+        $alphaTask = ProcessRequestToken::factory()->create([
+            'user_id' => $this->user->id,
+            'process_id' => $alphaRequest->process_id,
+            'process_request_id' => $alphaRequest->id,
+            'element_type' => 'task',
+            'status' => 'ACTIVE',
+            'is_self_service' => false,
+            'is_priority' => true,
+            'completed_at' => null,
+        ]);
+        ProcessRequestToken::factory()->create([
+            'user_id' => $otherUser->id,
+            'process_id' => $otherRequest->process_id,
+            'process_request_id' => $otherRequest->id,
+            'element_type' => 'task',
+            'status' => 'ACTIVE',
+            'is_self_service' => false,
+            'is_priority' => true,
+            'completed_at' => null,
+        ]);
+
+        $response = $this->apiCall('GET', '/tasks', [
+            'page' => 1,
+            'include' => 'process,processRequest,processRequest.user,user',
+            'pmql' => '(user_id = ' . $this->user->id . ')',
+            'per_page' => 15,
+            'order_by' => 'process_requests.case_title',
+            'order_direction' => 'desc',
+            'non_system' => true,
+            'processesIManage' => 'false',
+            'advanced_filter' => json_encode([
+                [
+                    'subject' => ['type' => 'Status'],
+                    'operator' => '=',
+                    'value' => 'In Progress',
+                ],
+                [
+                    'subject' => ['type' => 'Field', 'value' => 'is_priority'],
+                    'operator' => '=',
+                    'value' => true,
+                ],
+            ]),
+        ]);
+
+        $response->assertStatus(200);
+
+        $rows = $response->json('data');
+        $this->assertCount(2, $rows);
+        $this->assertSame(
+            [$zetaTask->id, $alphaTask->id],
+            array_column($rows, 'id')
+        );
+        $this->assertSame(
+            ['Zeta mandate', 'Alpha mandate'],
+            array_map(fn ($row) => $row['process_request']['case_title'] ?? null, $rows)
+        );
+    }
+
+    public function testNonAdminCanListTasksOrderedByCaseTitleDescAndFulltextSearch()
+    {
+        $this->user = User::factory()->create([
+            'is_administrator' => false,
+            'status' => 'ACTIVE',
+        ]);
+        $otherUser = User::factory()->create([
+            'is_administrator' => false,
+            'status' => 'ACTIVE',
+        ]);
+
+        $zetaRequest = ProcessRequest::factory()->create();
+        $alphaRequest = ProcessRequest::factory()->create();
+        $otherRequest = ProcessRequest::factory()->create();
+        $zetaRequest->forceFill(['case_title' => 'Zeta mandate'])->saveQuietly();
+        $alphaRequest->forceFill(['case_title' => 'Alpha mandate'])->saveQuietly();
+        $otherRequest->forceFill(['case_title' => 'Omega mandate'])->saveQuietly();
+
+        $zetaTask = ProcessRequestToken::factory()->create([
+            'user_id' => $this->user->id,
+            'process_id' => $zetaRequest->process_id,
+            'process_request_id' => $zetaRequest->id,
+            'element_name' => 'Review of the client name',
+            'element_type' => 'task',
+            'status' => 'ACTIVE',
+            'is_self_service' => false,
+            'is_priority' => true,
+            'completed_at' => null,
+        ]);
+        $alphaTask = ProcessRequestToken::factory()->create([
+            'user_id' => $this->user->id,
+            'process_id' => $alphaRequest->process_id,
+            'process_request_id' => $alphaRequest->id,
+            'element_type' => 'task',
+            'status' => 'ACTIVE',
+            'is_self_service' => false,
+            'is_priority' => true,
+            'completed_at' => null,
+        ]);
+        ProcessRequestToken::factory()->create([
+            'user_id' => $otherUser->id,
+            'process_id' => $otherRequest->process_id,
+            'process_request_id' => $otherRequest->id,
+            'element_type' => 'task',
+            'status' => 'ACTIVE',
+            'is_self_service' => false,
+            'is_priority' => true,
+            'completed_at' => null,
+        ]);
+
+        $response = $this->apiCall('GET', '/tasks', [
+            'page' => 1,
+            'include' => 'process,processRequest,processRequest.user,user',
+            'pmql' => '(user_id = ' . $this->user->id . ') AND (fulltext LIKE "%Review of the client name%") ',
+            'per_page' => 15,
+            'order_by' => 'process_requests.case_title',
+            'order_direction' => 'desc',
+            'non_system' => true,
+            'processesIManage' => 'false',
+            'advanced_filter' => json_encode([
+                [
+                    'subject' => ['type' => 'Status'],
+                    'operator' => '=',
+                    'value' => 'In Progress',
+                ],
+                [
+                    'subject' => ['type' => 'Field', 'value' => 'is_priority'],
+                    'operator' => '=',
+                    'value' => true,
+                ],
+            ]),
+        ]);
+
+        $response->assertStatus(200);
+
+        $rows = $response->json('data');
+        $this->assertCount(1, $rows);
+        $this->assertSame(
+            [$zetaTask->id],
+            array_column($rows, 'id')
+        );
+        $this->assertSame(
+            ['Zeta mandate'],
+            array_map(fn ($row) => $row['process_request']['case_title'] ?? null, $rows)
+        );
+    }
+}