It seems most bugs are fixed in 1.2.1, but I noticed some when playing 1.2.1.
- In Act 4 (aka Chapter 19), having No Talking (Part 2) active causes confusion as Bad News plays during the cutscene, and Carol and Evelyn will appear in the cells when Seles and Kaie fight the Researcher. I think this is due to both the main quest and side quest taking place in the CRC. A workaround/prevention is to not accept the sidequest before boarding The Bound Maiden and wait until the part of the story is cleared or use the Story Crystal to go back to an earlier part and finish No Talking (Part 2) before you board The Bound Maiden (since you can't return back to Iidra or the CRC once you arrive in in the Katoshi Isles/Shiode until you go through the Chroma Spring).
- You can use Nope (Chelsea) and Channeling (Kaie) as well as their upgraded skills from the menu. It seems the "Battle only" occasion wasn't set for these skills.
- In Mirio south of the Collector's house, it's possible to stand on top of the roof.
- Not a bug per se but one of the Ancient Fabrics can't be obtained after progression because the location it's in (Lanylisse) can't be visited unless the Story Crystal is used, or you beat Act 6.
- (Possibly a bug from 1.2 which may have been fixed 1.2.1) It's possible to have a duplicate of Liliana's default outfit.