[Stenzio]

I can tell you that it has to do with using the hot bar in order to summon the Youkai. Oddly it doesn't seem to 'always' cause it. Apparently another person had a similar issue in which installing a youkai caused the same issue I currently have.

Replicating it too, unfortunately, would at best lock me out of more Youkai. I can attempt to do so on another account/character though if this would help?