It's Amethyst's "gossip protocol" I think it's called. Instead of only retrieving from your specified relays, it grabs from the relays that everyone you follow is posting to. I'm not a fan of it myself, it makes granular control of relays pretty much impossible. I'm sure it has advantages, like it being less likely that you run into an event you can't see, but I'd much prefer to be able to specify my relays.