Developers for Picard are all doing so on a volunteer basis. They often pop in work on Picard stuff for a day or maybe a couple of days and then disappear back into the realm of RL. We were blessed to have @samj1912 really dig into Picard a while back, but sadly, even he eventually had to succumb to outside-of-MeB forces. It’s not that the issue isn’t worthy of developers’ time… it’s just that there’s not a whole lot of time to go around.
One of the people working on Picard wrote a lengthy response on the linked issues where he says “i’m not sure what is the solution to this”. Picard is an open source community project: if you wish to help move the issue along, read over (all) the comments written on the ticket. If you have any useful feedback/comments, then please do post them there—this in turn will hopefully help developers figure out a way to best deal with this case.
Maybe I don’t understand your initial issue, but isn’t the issue entirely cosmetic in that Picard just marks the release in its interface as having changed? The cover art is still downloaded and used/usable, no? And by you uploading it to the Cover Art Archive, it is now also usable by lots and lots of other people around the world?