This is complete speculation on my part but judging by the way that some frames of the owl house leaked pilot looked corrupted, I suspect that that video file (likely along with all the others in the leak) may have been fully wiped off a hard drive at some point and later recovered using specialized data recovery tools. It's technically possible to "undelete" a file but only as long as the hard drive sectors it used to be stored on haven't been overwritten with other data. This type of corruption never just happens by itself as far as I know, so this is the most plausible explanation to me.
Basically what I'm saying is that this file arrived on the internet in a bit of a rough shape and I would love to one day learn its story leading up to this point because it's clearly been through a lot.