AlricKyznetsov said:
Attempted to make a new artist tag when posting an image for an artist that did not exist yet. First, I ran in to several 500 errors (78cf6fa754013f328042d15bb4c232b7).

When it finally posted, somehow despite saying artist:vikiboy, it got made into a character tag instead. Of course, I was able to go to Tags and manually change the tag type, but I'm not sure why it defined it as character when I explicitly said artist.

You're lower than priviliged, so the error to change the category is expected

It changing into a character tag somehow isn't. Did you check if perhaps someone else just happened to change the type of the tag at the same time as you adding it?