I am having the same issue with two of my characters, marauder and pugilist. This seems to occur right after I cast a spell. I can get it restarted by "forcing" an attack with broad swing, etc., but if those attacks aren't available, you have little recourse. At this point I will probably stop playing. I have put up with a lot of changes for this game, but putting out this patch with what appears to be little if any testing of the auto-attack causes me to reconsider if this is worth it.