I remembered something else! This is a weird one. I've noticed that when Kana is in my party, sometimes the Skeletons or the Phantom that he summons will get "stuck" on the map, refusing to de-spawn when their time is up. They're not controllable, it's just like their images are there. This doesn't happen consistently, but when it does, this "afterimage" of the summons will then be persistent in a consistent spot on EVERY map for the rest of the game. This looks really weird, and forces me to pretend that I'm being followed at a distance by a gang of spooky bois for most of my playthrough.
I'm far from certain, but I *think* it may be related to if Kana (or the Chanter in question) is knocked out while the summon spell is active? That may or may not be the only trigger. In any case, it would be *fantastic* to see a fix for this if possible.
This bug is also reported elsewhere (only for skeletons, but I have definitely observed it for Reny Daret the Phantom). See: