Lost uploaded files to wiki , just links remain


We migrated to Gitlab CE 16x a couple of months ago and 2 days ago to 16.6.5. I mention this because we have detected some files uploaded to a project wiki, with the link to them but with empty content, I mean size 0, their link look well, hashed, but they are not even in the server, does this ring a bell to you?

Thanks in advance,

Jose M.