My partner and I have a 'sea lab' that we created off an island. We made a nautilus/heart of the sea beacon. It gave us sight for a far distance underwater, but since this update, every time we go underwater now it's super dark and we can't see anything but about 50 blocks in front of us. The glass we're using for the structure has also grown a level of water beneath it so you can't see through them anymore, which is a real problem when building and hasn't ever affected us before.

When going downstairs where the building starts to go underwater, it's also very dark–like our torches aren't working. After 30 seconds or so it lit up finally, but underwater is still really hard to see, despite the beacon buff.