If you refer to dervishes. It is the normal interaction of the dervishes with projectiles. It is not a bug
It can be. If your hardware is overheating/unstable/not supported or if you use incompatible software or old drivers.
But in this case there is most likely a bug with the used fmod file/implementation in diablo 3 which leads to freezes.
The technical support is not able to fix bugs.