After using The carnevil for a while now, I haven 't found the Cause of the bug, but for anyone getting this. When you notice they aren't Shooting take damage and heal with your Heal potion. 100% of the time during runs this has worked to fix the issue, Hopefully blizz will fix soon, They already seem to know about the Bug.
Title says most, Cannot get it to happen outside of a Greater rift, Doesn't matter if Solo or in groups.
I took a little video to show it happening (Sadly in a record run) And it seems from watching it, I got them to start shooting again after pressing my potion, Seems dumb but considering how the snapshotting with stricken was, i wouldn't be surprised.