Cut doesnt mach after rendering

Hello, can somebody help me out? i noticed that issue in my project only in some parts of the timeline with severel short cuts (about 1 sec). Like you can see in the attached video before rendering the cut fits exactly how it should be... when i move foreward frame by frame you can see where the cut is and the next clip begins. But after i render that part there is the issue.. now, as you can see there i have to move two frames foreward to see the result in the preview and it doesnt match exactly how i did set the cut.

i tried for hours but i cant solve this problem and its just random in a few clips of my project.