Creation date of Numbers file in iCloud reset?

The creation date of one of my Numbers files in iCloud has been reset. Browsing through the previous versions of that file, it seems that the creation date has been reset to a much more recent modification date.

What happens when you restore a version older than this point in time? The creation date will just remain the same, which means that the modification date is then older than the creation date. What?

It’s not like there’s data loss or anything (except metadata), but this doesn’t make me trust iCloud’s integrity. Does anyone know what could be going on?