I have recently updated to PM 6, but I'm encountering an issue where contact sheets no longer show thumbnails for my video files. These files are all in .mov format, and while I can hear the audio, the images are not visible. Can you help me identify what might be the issue? I am using a 2018 MacBook Pro with OS Ventura 13.2.1, and my Photo Mechanic version is 6.0, build 6784 (409cf99).