Deep rebind attribute callbacks after clone

src/BaseHtmlElement.php

@@ -395,6 +395,21 @@ public function renderUnwrapped()
 
     public function __clone()
     {
+        $copy = $this->copy();
+        if ($copy !== null) {
+            $copy->then(function (SplObjectStorage $copies): void {
+                foreach ($copies as $ignored) {
+                    // SplObjectMap always iterates over the attached objects that
+                    // are the elements before they have been cloned.
+                    // But we want to work with the cloned element.
+                    $copy = $copies->getInfo();
+                    if ($copy instanceof self) {
+                        $copy->getAttributes()->rebindAttributeCallbacks($this->objectId(), $this);
+                    }
+                }
+            });
+        }
+
         parent::__clone();
 
         if ($this->attributes !== null) {