diff --git a/src/pocketmine/tile/Sign.php b/src/pocketmine/tile/Sign.php
index 5c4f13106..2a9afcdff 100644
--- a/src/pocketmine/tile/Sign.php
+++ b/src/pocketmine/tile/Sign.php
@@ -155,7 +155,7 @@ class Sign extends Spawnable{
 
 		$ev = new SignChangeEvent($this->getBlock(), $player, array_map(function(string $line) use ($removeFormat){ return TextFormat::clean($line, $removeFormat); }, $lines));
 
-		if(($creatorUUID = $this->namedtag->getString(self::TAG_CREATOR)) !== null and $creatorUUID !== $player->getRawUniqueId()){
+		if($this->namedtag->hasTag(self::TAG_CREATOR, StringTag::class) and $this->namedtag->getString(self::TAG_CREATOR) !== $player->getRawUniqueId()){
 			$ev->setCancelled();
 		}