My lighting seems to be completely bugged. I had this problem a few years ago, and the 2.3 multiplayer update mostly fixed it, but it seems to be back worse than ever. sections of cave roof are dotted with between pitch black and little spots of light, and entire portions of my structures are rendered in black. I have been unable to fix it via settings tweaks, though I'm sure I probably missed a few.
I have tried deleting and regenerating, and it rebuilds the LODs the same way each time.
For context, I am playing on a modded server (that does not have alex's caves) and I am not using server sync, my data is kept completely separate. (a paranoid holdover from the days when it would randomly delete all data on join/sync)