Yeah, its a super niche issue I think, exacerbated by the fact we insert community blocks for all new users, which further impacted on how badly postgres struggled with it. Schwim had 10ish communities also that he had blocked personally, but we had since banned the mods of from .zip, and the way lemmy handles these is basically to hide them from the user in the blocked communties screen, hence the ghost-blocks, so all around it was just a mess. Thankfully such a simple* fix.

*It took hours and hours and hours.