diff --git a/includes/dropins/page-cache.php b/includes/dropins/page-cache.php
index 47d1192..2adf875 100644
--- a/includes/dropins/page-cache.php
+++ b/includes/dropins/page-cache.php
@@ -62,10 +62,26 @@
 // Don't cache page with these user agents
 if ( isset( $powered_cache_rejected_user_agents ) && ! empty( $powered_cache_rejected_user_agents ) ) {
 	$rejected_user_agents = implode( '|', $powered_cache_rejected_user_agents );
-	if ( ! empty( $rejected_user_agents ) && isset( $_SERVER['HTTP_USER_AGENT'] ) && preg_match( '#(' . $rejected_user_agents . ')#', $_SERVER['HTTP_USER_AGENT'] ) ) {
-		powered_cache_add_cache_miss_header( "Rejected user agent" );
+	if ( ! empty( $rejected_user_agents ) && isset( $_SERVER['HTTP_USER_AGENT'] ) ) {
+		$pattern        = '#(' . $rejected_user_agents . ')#';
+		$error_occurred = false;
 
-		return;
+		set_error_handler(
+			function () use ( &$error_occurred ) {
+				$error_occurred = true;
+			},
+			E_WARNING
+		);
+
+		$match = preg_match( $pattern, $_SERVER['HTTP_USER_AGENT'] );
+
+		restore_error_handler();
+
+		if ( ! $error_occurred && $match ) {
+			powered_cache_add_cache_miss_header( "Rejected user agent" );
+
+			return;
+		}
 	}
 }
 
@@ -150,7 +166,21 @@
 	if ( ! empty( $powered_cache_rejected_cookies ) ) {
 		$rejected_cookies = array_diff( $powered_cache_rejected_cookies, $wp_cookies, $comment_cookies, ['powered_cache_commented_posts'] );
 		$rejected_cookies = implode( '|', $rejected_cookies );
-		if ( preg_match( '#(' . $rejected_cookies . ')#', var_export( $_COOKIE, true ) ) ) {
+		$pattern          = '#(' . $rejected_cookies . ')#';
+		$error_occurred   = false;
+
+		set_error_handler(
+			function () use ( &$error_occurred ) {
+				$error_occurred = true;
+			},
+			E_WARNING
+		);
+
+		$match = preg_match( $pattern, var_export( $_COOKIE, true ) );
+
+		restore_error_handler();
+
+		if ( ! $error_occurred && $match ) {
 			powered_cache_add_cache_miss_header( "Rejected cookie" );
 			return;
 		}
@@ -173,7 +203,21 @@
 			continue;
 		}
 
-		if ( preg_match( '#^(' . $exception . ')$#', $_SERVER['REQUEST_URI'] ) ) {
+		$pattern        = '#^(' . $exception . ')$#';
+		$error_occurred = false;
+
+		set_error_handler(
+			function () use ( &$error_occurred ) {
+				$error_occurred = true;
+			},
+			E_WARNING
+		);
+
+		$match = preg_match( $pattern, $_SERVER['REQUEST_URI'] );
+
+		restore_error_handler();
+
+		if ( ! $error_occurred && $match ) {
 			powered_cache_add_cache_miss_header( "Rejected page" );
 
 			return;