I don’t understand the relays.
Discussion
This might help.

I believe relays send events to each other as well..
Not if they are standard compliant: "A relay doesn't talk to another relay, only directly to users."
Thanks for responding with a source. However, even if all relays follow the standard, clients can broadcast events to the relays they are connected to, which can very often lead to a note from one user on one relay reaching the feed of a user on a different relay, by for example a repost/broadcast from a third client connected to both relays. Correct me if I am wrong
That's probably how it works. I didn't find it in the protocol-description, though.
Thank you