diff --git a/Sources/Board.php b/Sources/Board.php
index ac0c51fb7c..4c3e5f3e2e 100644
--- a/Sources/Board.php
+++ b/Sources/Board.php
@@ -485,7 +485,7 @@ public function __set(string $prop, mixed $value): void
 
 		// Special handling for the category.
 		if (($this->prop_aliases[$prop] ?? null) === 'cat[id]') {
-			$this->cat = Category::init($value);
+			$this->cat = Category::init((int) $value);
 
 			return;
 		}