Confirmed it's still happening in 1.16.3. Really hoping this ever gets fixed again.
*edit* it seems that my issue with this in 1.15.1 is that the eggs must not have any block within 2 above them for the drowned to pathfind to them. I can place a block 3+ above them and they pathfind just fine, but as soon as a block is 2 above the egg they no longer see it
Confirmed in 1.16.3. Blindness + Nightvision = everything completely dark. My laptop is not on power saving mode. I do have an NVIDIA graphics card.