accurate
what's going on is probably that soejima is drawing these in his lunch break while he's working on persona 5!
Probably not that far from the truth, tbh. P5 is the priority in all ways, and a game that Soejima presumably has a lot more sway over. They're probably in crunch right now, so he'll be getting these things out of the way ASAP. And Ultimax requires a lot more work from Soejima than P4D or PQ, so that's probably why the lower quality here isn't seen in either of those games.