And no, @Ivo did nothing to achieve this. I find this a very creative bug.
To clarify, I tried to upload a screenshot but it wasn’t allowed because I’m a new user. Instead it ended up as my profile background. Quite peculiar bug, I haven’t been able to reproduce it a second time.
We need a repro otherwise we can’t fix it.
@ivo Have you cleared the background image since?
Also, what upload method was used (From Device, from Web or drag n drop)?
Yes, I’ve cleared my background image since. The upload method was drag and drop.
I have seen reports that this can happen if you have the editor open on the user page, images added to the editor will “accidentally” become your new profile background too.
Yes I believe I’ve fixed this one.