Is me again, i keep breaking Rf!

I have a retime curve, nothing fancy, but on one of the keyframes (it is 100% speed , keyframe 1, keyframe 2 , 20% speed)i get 0kb files..just on the frame the keyframe is on,,i tried all options on the retime tool..and even loaded the curve on other files..same issue.
this is actually not as weird as a previus file where on the frame the keyframe was on, i would get some 200 particles less..that was really odd.
this is on the latest rf2013...7.1.3.0152
any ideas on this oddity?
fanx