Visual glitch in FTB Revelation with SEUS Renewal shaders [closed]
Solution 1:
The glitch is caused by collision between Botania shaders and SEUS shaders.
Setting B:shaders.enabled=false in config/botania.cfg and reloading whole game after this changed solved the issue.
Source: https://www.reddit.com/r/Minecraft/comments/8ldx02/random_shadows_with_shaders/