The only was I know of this can happen is if your time base is off. Say you start working in a 30 fps sequence, then copy everything over to a 24 fps sequence, then the end of some cuts may very well end up between frames. You'll have to go through and adjust every edit to land properly on the frame.
Thank you for answering, but with encore i always had 24 fps. I cant remember if this was the case when i had this problem in premiere.
in encore the cut is right there where the frame starts, but if I make the video and audio (together) shorter, then it happens.
I believe that you will always be better off, if you establish the Duration of your PrPro Timeline, and then NOT try to adjust the Timeline in Encore. Encore is not an NLE, and really, really wants to have Assets "ready to go," rather than in need of additional editing.
with encore i always had 24 fps.
Yeah, but the Encore timeline assumes a 30 fps time base. Either your 24p original has the 3:2 pulldown it in already, making it truly 30 fps, or it has the appropriate flags inserted, which makes Encore treat it as 30 fps.
I don't think there's any way around that with Encore. It's just the nature of the NTSC beast.