When auto-ing on a quest mob I normally get one of two messages. Either that I found the item I am looking for and I have X left to find OR jut that I have X left to find. On occasion though, it displays nothing as if I either do not have the quest or am on the wrong mob. It will occur maybe once in 500 autos.
Periodically, in the middle of a run of autos when the action timer has counted down to 0.0 the auto run will just stop regardless of how many autos are left. This occurs ever few runs of autos (I have 130 autos).
Also, during a run of autos I occasionally get a pop up that says "Please wait until your current actions has finished". Happened a lot yesterday. Each time I have to refresh.
All this is when I am running on Chrome. No issues at work on Firefox or on my phone running Dolphin.