Ascension, Pre 2.0 Issue, Assistance Requested

So Ascension 2.0 came out while I was running BG2 again for the first time in a long time. I saw it, and decided I would do a fresh install of BG2 after I completed my current run. Anyways, I get into ToB and start WK, and am about to fight Improved Tougher Demogorgon... but he just stands around and lets himself be killed. I don't have SCS or any other mod that addresses Demogorgon, so I'm assuming this issue arises from old ascension and enhanced edition, and I was wondering if anyone knows of a workaround. If not, no biggie, I'll just choose to seal him in instead. I'd rather do the fight if at all possible, but if not, I'll survive.