Trick or Treat Exchange

I'm going to poke my co-mod about this also (because they did most if not all of the heavy lifting), but I wanted to at least note that you're not alone with recent experience with fuxxored AO3 nom tags.

We had (in August) tags disappearing, hopping fandoms despite being hand-placed, and even duplicating across two fandoms nominated by the one person (thus freezing their ability to add to their nom list).

I think something's gone massively screwy with AO3's exchange code, and getting worse.