Can you be more specific? I know with the initial v0.4 release on Patreon there was a bug where he'd show up while Ollie is laying on the floor, but more recently I've heard ppl just reporting that his sprite shows up at the "the party continues on" at the end of Ollie's digestion route.
It also might be that you were loading an old save and certain variables were not checked correctly because of it, so maybe try starting a new game and see if it still happens?