I noticed, that Brodequin did put out a new single a few today ('Of Pillars and Trees'). It's from a forthcoming album/EP I suppose, because it has a cover art with title 'Harbinger of Woe'.

https://www.metal-archives.com/albums/B ... es/1205395

There's loads of digital singles these days, but many has its own artwork at least. Are this kind of single cuts valid where a single uses cover art of another release?

^This one should be removed.

To my understanding, this is how digital singles have been treated thus far:

Multiple singles with the same cover art aren't valid.
-Exception: When the title of each single is written on the picture.

Singles using the same cover art as the main release they're taken off of aren't valid.
-Exception: When the single has the same title as the EP or full-length.

I don't think this is true. If it has the exact same art, it's invalid as far as I've seen. I've submitted a bunch of release/version invalid reports for this exact scenario and never been told otherwise.

^Good to know. I come across such instances every now and then but I didn't know they should be flagged for removal.

Also I believe that's only the case for digital releases. If there's a physical single and physical album that share the same art I think that's valid.