This release has been deleted yet it's still present at the cover art archive:
https://archive.org/details/mbid-e718c60b-fee0-4292-9c38-fc02ef20f812

And despite the "add cover art" edit having failed due to the removal it's also still present in CAA (MBS-4753):
https://musicbrainz.org/edit/76231226

Another example of a deleted release that had pending cover art additions and wasn't removed from the IA:
https://musicbrainz.org/edit/78143886

An awkward example where a troll added NSFW images:
https://musicbrainz.org/edit/78171681