If you try to share the video before processing is finished, you are usually sharing the COVER.mp4 preview.
It is a generic filename often used by artists or creators for a video cover of a song (e.g., "Misty Cover.mp4"). Cover.mp4
While it could refer to any of these, I am providing a text focused on the context, as it is a specific technical term associated with that filename. Understanding COVER.mp4 in Google Pixel Video Boost If you try to share the video before