Fix

src/EventHandler/AbstractButtonQuery.php

@@ -10,9 +10,16 @@ abstract class AbstractButtonQuery extends AbstractQuery
     public readonly string $data;
 
     /** @internal */
+
+    /**
+     * @readonly
+     * @var list<string> Regex matches, if a filter regex is present
+     *
+     */
+    public ?array $matches = null;
     public function __construct(MTProto $API, array $rawCallback)
     {
         parent::__construct($API, $rawCallback);
-        $this->data = (string) $rawCallback['data'];
+        $this->data = $rawCallback['data'];
     }
 }

src/EventHandler/AbstractQuery.php

@@ -14,12 +14,6 @@ abstract class AbstractQuery extends Update
      * @var int Global identifier, uniquely corresponding to the chat to which the message with the callback button was sent. Useful for high scores in games.
      */
     public readonly int $chatInstance;
-    /**
-     * @readonly
-     * @var list<string> Regex matches, if a filter regex is present
-     *
-     */
-    public ?array $matches = null;
 
     /** @internal */
     public function __construct(MTProto $API, array $rawCallback)

src/EventHandler/Filter/FilterCallback.php

@@ -17,6 +17,6 @@ class FilterCallback extends Filter
     }
     public function apply(Update $update): bool
     {
-        return $update instanceof AbstractButtonQuery && $update->data === $this->content;
+        return $update instanceof AbstractButtonQuery && (string) $update->data === $this->content;
     }
 }

src/EventHandler/Filter/FilterCallbackRegex.php

@@ -20,7 +20,7 @@ class FilterCallbackRegex extends Filter
 
     public function apply(Update $update): bool
     {
-        if ($update instanceof AbstractButtonQuery && \preg_match($this->regex, $update->data, $matches)) {
+        if ($update instanceof AbstractButtonQuery && \preg_match($this->regex, (string) $update->data, $matches)) {
             $update->matches = $matches;
             return true;
         }