Shader ver: Epoch shader ver v1.3.1
Shader loader: iris mc1.19.4-1.6.3
Issue: I noticed that for almost every profile, when in the nether, the shadows break a little. the problem is that they are almost black, and when breaking blocks in places where there is a shadow, the particles of destruction are very bright. I also noticed that the shadow falls strangely on the sides of some blocks.

Regarding the dark shadows, you can increase the Minimum Light setting in [World] -> [Lighting] -> Minimum Light to make the shadows not be completely black.
I have also just added a workaround that darkens particles in the nether.