When I attempt to cut an MP4 or trim, the video clip sequence is corrupted (UNDO usually restores). A Trim can turn a portion of the CLIP black during editor's playback. A cut can kill the sequence. I captured a Video from my iPad to MP4 (using an AirPlay recorder) and after cutting portion the frame sequence gets corrupted, where closing iPad APP occurs out of sequence. This adds hours to editing. I used to have similar issues with Camtasia 8 on MOV videos. This is killing productivity, and destroys the experience.