Thumbnails not generating for video files in finder
I've been doing some video editing for work recently and have noticed that thumbnails are not generating for all video files within different folders in finder. This is particularly evident when working with larger folders (1000+ files), where thumbnails are generated to a certain point when scrolling down before stopping. This is occurring on my older Macbook Pro 2015 as well as my newer iMac 2019, both running the latest version of Big Sur and desktop HDD for video storage. Video files are all mp4s (not mkvs). Have tried clearing finder preferences and relaunching, but will always stop generating thumbnails after a certain point. Is this a general issue on current macOS or is there a limit for the number of thumbnails that can be produced in a folder at one time?
MacBook Pro 13″, macOS 11.4