It's pretty common to see remixers freely releasing unauthorised remixes (in soundcloud/bandcamp/youtube) of songs they don't have the rights for. It's pretty much an official release for the remixer, but not so for the original artist. Right now, it's not clear how to add those:

Always as standalone recordings? (even though a lot of them have proper covers)

As Other+Remix releases under the original artist? (and with what status?)

As releases in the original song's RG, when applicable? (and with what status?)

As releases under the remixer?

We should discuss and decide something about this.