diff --git a/src/Type/ObjectType.php b/src/Type/ObjectType.php
index 3e755bab60..b69fd0e5d1 100644
--- a/src/Type/ObjectType.php
+++ b/src/Type/ObjectType.php
@@ -1746,7 +1746,7 @@ public function getClassReflection(): ?ClassReflection
 
 		$classReflection = $reflectionProvider->getClass($this->className);
 		if ($classReflection->isGeneric()) {
-			return $this->classReflection = $classReflection->withTypes(array_values($classReflection->getTemplateTypeMap()->map(static fn (): Type => new ErrorType())->getTypes()));
+			return $classReflection->withTypes(array_values($classReflection->getTemplateTypeMap()->map(static fn (): Type => new ErrorType())->getTypes()));
 		}
 
 		return $this->classReflection = $classReflection;
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13985.php b/tests/PHPStan/Analyser/nsrt/bug-13985.php
new file mode 100644
index 0000000000..0224007d36
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-13985.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Bug13985;
+
+use SplObjectStorage;
+use function PHPStan\Testing\assertType;
+
+function example(mixed $param): void
+{
+	if ($param instanceof SplObjectStorage) {
+		foreach ($param as $key => $value) {
+			assertType('int', $key);
+			assertType('object', $value);
+		}
+	}
+}
+
+class X {}
+
+/**
+ * @param SplObjectStorage<X, int> $splObjectStorage
+ * @return void
+ */
+function genericExample(SplObjectStorage $splObjectStorage): void
+{
+	foreach ($splObjectStorage as $key => $value) {
+		assertType('int', $key);
+		assertType('Bug13985\X', $value);
+	}
+	assertType('int', $splObjectStorage->getInfo());
+
+}