diff --git a/src/Type/TypeCombinator.php b/src/Type/TypeCombinator.php
index 6dd1fd1bf0..fb6eba781a 100644
--- a/src/Type/TypeCombinator.php
+++ b/src/Type/TypeCombinator.php
@@ -326,6 +326,14 @@ public static function union(Type ...$types): Type
 			$scalarTypes[$classType] = $scalarTypeItems;
 		}
 
+		if (count($types) > 16) {
+			$newTypes = [];
+			foreach ($types as $type) {
+				$newTypes[$type->describe(VerbosityLevel::cache())] = $type;
+			}
+			$types = array_values($newTypes);
+		}
+
 		// transform A | A to A
 		// transform A | never to A
 		$typesCount = count($types);