The expression return $this->container-...lBundleMetaData::class) could return the type null which is incompatible with the type-hinted return Zikula\CoreBundle\Bundle...BundleMetaDataInterface. Consider adding an additional type-check to rule them out.
This check looks for calls to methods that do not seem to exist on a given type.
It looks for the method on the type itself as well as in inherited classes or
implemented interfaces.
This is most likely a typographical error or the method has been renamed.