Hello,
I'm aware that there are already a few talking about this here, but I post this in the hope that the more who speak up and report it that Larian will resolve this quickly.
BG3 is completely broken upon entering Act III since the release of patch 4. I'm on PS5 and have played close to 700 hours, and it is only since patch 4 that I have ever experienced this. My older play-throughs of different Tavs during ealier patches still perform perfectly fine.
Since patch 4, the entire environment in Act III is shut down — companions do not follow Tav, NPCs walk in place or completely vanish, unable to interact with anyone or anything, unable to select different companions, cannot save, and cannot reload. The lag will resolve for about 15 seconds every 10 minutes. This is a profound problem and extremely unfortunate that this happened. BG3 is an amazing game, an absolute work of art, and loved by so many; but it feels like we're still in beta testing here and it's incredibly frustrating, especially after investing 50+ hours to get to Act III. There's the expectation that problems as big as these will have been resolved before the launch of a full release. It is an expensive game that is currently unplayable. Please fix this asap Larian.
I Am on PC as well i have the same problems, i have two separate play through's on hold now because it is so broken. I started a new run and ACT 1 works perfectly.