Fixed ElementCondition::$elementType being reset in __construct()

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Fixed styling issues with Template field layout UI elements’ selector labels.
 - Fixed a validation error that could occur when saving a relational field, if the “Maintain hierarchy” setting had been enabled but was no longer applicable. ([#15666](https://github.com/craftcms/cms/issues/15666))
 - Fixed an information disclosure vulnerability.
+- Fixed a bug where element conditions could have their `$elementType` property reset.
 
 ## 4.12.0 - 2024-09-03
 

src/elements/conditions/ElementCondition.php

@@ -73,7 +73,10 @@ public function __construct(?string $elementType = null, array $config = [])
             throw new InvalidConfigException("Invalid element type: $elementType");
         }
 
-        $this->elementType = $elementType;
+        if ($elementType !== null) {
+            $this->elementType = $elementType;
+        }
+
         parent::__construct($config);
     }