Storm Totem casts the bolts very slow from time to time. Its very random and doesnt matter if its been stunned or not, it just starts to cast very very slow, like once every 1.5 seconds even though it should cast very fast with all my castspeed I have on it. Its awful to play at this state
I (and other people as well) also encountered this. I think it may not be random. It definitely occurs when one of the following hostiles are near (at least these are the ones I observed the bug with): void leech, desert stinger, phrax, fallen osprix, void maggot, rotfly, storm wisp.