I had to rename the old log file since it was 2 GB, A new log has started, I will check it when it happens again. It only happens on named mobs that have adds. It seems to stop if I switch from pullertank to sictank during the fight, after the named is dead, I can switch back to pullertank and its business as usual. The only new thing that I have done is added "mq2say=1" to my MQ.ini file yesterday, which should have nothing to do with it. I also double checked that roles were setup correctly, PU was not setup on the tank, set it. Not sure if that would of caused it since he is still set as MT/MA.
Thanks for help, will keep an eye on the log for more clues.