My guess is this is also related to kind 3 and your large follow count. Some relays don’t accept more than 500 tags in an event. Others 1000. Some 2000, some 5000, etc. Any relay that doesnt accept as many tags as you have follows will not accept your updated contact list event.

As such, you have a race condition where the follows list you get back can differ from each relay depending on their limit. Depending on the client implementation this could cause people you have unfollowed to appear followed again or appear in your follows timeline.