Yn 600ex Problems

This is a video I made for Yongnuo customer support describing issues I am having with their Yn600ex flashes. These issues are only starting after about 1hr 30 min of shooting with about 225 shots. So I m not sure if them being powered on that long is the issues or the number of shots. Either way it makes them useless for event photographers. I had 5 of these and tested all five as the master as well as with a different camera and found the same problem with all combinations. I would stay away from these u br, br,