I have been noticing premiere projects and after effects projects vanishing . I recently was able to reproduce this because fortunately, we have a backup system in place and was able to recover the deleted project, and reproduce it.
I have a dynamically linked after effects project with som fottage that became unlinked.
I choose "edit original" from premiere and relinkd the footage that was unlinked.
When I went into premiere it said the after effects project (that was just there) was offline.
When I looked in the folder that the ae project was in, it was empty
https://youtu.be/a4DBbu6js4c