Given a tracker that we will call "Parent" with no "Title" semantic defined, and given that tracker is also parent in a tracker hierarchy of some tracker that we will call "Child", when you edit an artifact in "Child" tracker and you use the new artifact links edition, there will be a PHP error like the following:

PHP Fatal error:  Uncaught Error: Typed property Tuleap\Tracker\Artifact\Artifact::$title must not be accessed before initialization in /usr/share/tuleap/plugins/tracker/include/Tracker/Artifact/Artifact.php:710

There should not be an error if the tracker has no "Title" semantic.

Workarounds

1. Define a Title semantic in the Parent tracker
2. Uncheck the option for the "New artifact links edition" in the Child tracker