Also saw that. Lost my follows several times trying different relays.
This was helpful:
I use the “Nostore” extension on iOS. (Works great). It stops and asks for permission when a Nostr client wants to do anything.
It’s shows the pending event as an xml page of what it’s going to do.
At one point I was following ~3500 accounts and the event to add/remove a contact was miles-long! Had to scroll for like 5 minutes to get to the bottom and approve it.
Updates to follow/following lists won’t scale. Hopefully this will get visibility in a Nip and be improved to not include all accounts list for changes.