[ViTheVault]

Thanks for the quick reply and hints. I'll try it out next time the issue appears.
I transcoded to .mp4 (H264) And seems to work well now...
Video's are on an ssd. And there is no difference between them. It Just doesn't make sense to me... but hey... Sometimes **** have to happen.
And I Just learned that there is a difference in sync off set depending on the codec you use... We do learn every day!
Thank you for your time

@moderators you can close this threat born out panic. Thank you