When checking edit history, I notice all Add cover art edit have empty picture despite those pictures are still available in Cover Art tab.

https://musicbrainz.org/search/edits?auto_edit_filter=&order=desc&negation=0&combinator=and&conditions.0.field=release&conditions.0.operator=%3D&conditions.0.name=Music+for+the+Masses&conditions.0.args.0=680062&conditions.1.field=status&conditions.1.operator=%3D&conditions.1.args=1&conditions.1.args=2&conditions.2.field=type&conditions.2.operator=%3D&conditions.2.args=314&conditions.2.args=225%2C223%2C311&field=Please+choose+a+condition

I notice in these edits, the release link is broken.
It means the release to which uploads were made has been merged into another one I think. And there would be an MBID mismatch on CAA / MB.

Newer, after merge, Add cover art edits are indeed OK.

For instance https://musicbrainz.org/edit/56277706 looks for https://archive.org/0/items/mbid-b0b1d17d-23c0-4970-b046-70c79d9bafd0/mbid-b0b1d17d-23c0-4970-b046-70c79d9bafd0-21046273955.jpg instead of https://archive.org/0/items/mbid-39591a1c-3da9-3ac3-a56e-cd929a1df8a4/mbid-39591a1c-3da9-3ac3-a56e-cd929a1df8a4-21046273955.jpg (newer MBID)