Is this a Yorick bug or not?

I went into a custom game and noticed this. If you use new Yorick's Q on any structure it will deal the empowered damage (as it should), however after using this empowered auto you can then proc the same Q on a minion or champion for the same empowered auto. To make it clear and replicate it:

1. Activate Q, hit structure (deals bonus Q damage)
2. Hit minion/champion (still deals empowered Q damage and will create a grave if the target dies

Is this intended? I didn't see anything mentioning it on his Q ability or in the spotlight.