Hi, I''m using minecraft !.12.2 with forge, litelaoder and optifine
Wolves used to attack mobs if the mobs attacked you, and they definately attacked skeletons anywhere.
They are not doing either of those two anymore. I can be surrounded by skeletons in the wild, and the wolves just wander around like they are in a safe place.
This only started happening for me in 1.12.2