okay here is the list things i tried.
i did set my project settings to match the media
reinstalled vegas pro (all the settings default)
changed fps to diffirent numbers like (30-60-59.94) and tried to play video
still same video has same problem. nothing changed
BUT!!!! things i forgot to said
now im sure its not about how long is the video because i tried all my videos, some of the videos are very long like 1 to 2 hour, some of them short like 10 min. every one of them working fine (with the settings you saw on the video)(default or not not dosent matter works fine.)
for example there is 30 video i recorded only 5 of them have this problem.
i started thinking the problem is about shadowplay because sometimes when i was recording i just press ALT+TAB and go to desktop, with that way recording just pauses so that could make audio issue i guess.
AND THE İMPORTANT THİNG!
when i play these audio problem videos withany media program like ( windows media player , kmp player ) i dont have any problem. audio is synced with video. just when i import to vegas this problem starts.
and im not sure but my monitor is 144 hz so vsync is unlocked in any game but recording settings on shadowplay is 60 fps limit. can that make problem between the video and audio when i put to vegas pro i dont know..
BİG THANKS TO WHO helped me but my problem is not solved i will show more detailed video about my problem soon.