@jamies
If you've added the transferred product to the same cross sell collection that has already has a cover photo/media file, I believe this is expected behavior that it picks up the collection's cover photo if it hasn't got it's own cover photo yet (I could be wrong though)
As a test - remove it from that cross sell collection and put it in another collection (not cross sell) that doesn't have a media file assigned, wait for the site to catch up indexing wise (could be a couple of days) and see if it clears it?
It could be glitching if your product is in two cross sell types for example - it's getting confused. Have you set your transferred product's preferred collection (or is that option not available?)
It does help the tech team though if you can link to the product/collection that's misbehaving and am sure they'll get to the bottom of it
