Thanks Donald. I was in Manual exposure mode . Just did some more testing and was able to reproduce the issue . When shooting in a really dark room it does fail to refresh quickly. As I was in a nightclub it was really dark with the exception of various spot lights throughout the room. I was shooting at 1600 iso at f 2.8 and had the subject near one if the spots so was able to get away w 1/16 power. But because the spot where the light was set up was really dark this was effecting the refresh. I still cannot figure out why.... ??? Are there any other triggers anyone can recommend that for sure don't have this issue ? Thanks !!