It might be that relays cannot decide whether you have him blocked or not. If you block someone it has to transmit across the system. Maybe a user block has higher priority than does an unblock. So you have to fight against relays for a while trying to enforce your prior rule against your changing and fickle human indecision. I think I might have had the same issue. We blamed a poor dev who had to assume malfeasance on Verita's side.