Same here. As soon as I got to the Underdark it started glitching. Pitch black for sometimes 10 seconds or so. Then it comes back and I can see.

On a positive note, I revamped a suggestion I had about dungeon lighting. Pitch black definitely sucks. Some lighting is good, but sunlight in the Underdark especially has to go...

But so does the pitch black glitch. 🤕