Seems like since the latest patch, the puzzle to get into the Underdark appears to be a little borked. Panels will straight up disappear or swap around, making it pretty impossible to complete.
Can't confirm if this is in general, or if that save in particular got bugged-- friend and I started over regardless to redo our current campaign, but it definitely ground our first game to a halt.
Other than that, there are various bugs where different actions or dialogue trees in conversation/interaction will completely freeze and not progress. Trying to dig through the grave near the Grove, for instance, just causes my character to become locked in the cutscene with no way to exit and no further dialogue. I had to kill them and ressurect them at camp in order to free them without reloading. Similar things have happened with a few conversation options with some companions, such as Astarion.
