In the last version (1.16.1) it didn't affect the piglin's animations but in 1.16.2 it now does. The piglin brute's spawn egg is also a dark yellow color when it's supposed to have it's usual spawn egg color. I'm not even sure in the shaders pack I'm using is affecting them like this. If so, Piglins and Brutes should be fixed even if a shaders pack is on.