Cryangar bugs with Necromancer

Hi, i play with Necromancher and while doing Purge the Depth quest my skeletal captain keep randomly disappearing without any reason and i can’t activate it again. As a temporary solution i can simply swap the ability with another, than swap back my skeletal captaion and he comes back, but after a while the issue start again… and again. Sometimes even my golem stop being activatable but it’s less frequent.
Also some chest spawns inside walls and are not reachable.
None of this happens outside of Cryangar.