Are you sure your playback software (player, game engine) doesn't have a fadeout? That is a really short sound, so you might want to look into settings.
Also, have you tried to open the reversed file in audition after export? Is it cut off or full?
if its full -> check your playback settings
if its short -> use any other free software like ...
I found the cause of the problem: Low disk space (~30 MB). It seems that the .flp projects need more to save all their data.
I fixed the problem: i used the existing backup effects and i rebuild the rest from scratch.
Thank you for your time!