This bug has been reported before, but those topics are closed due to age so this post.
Exactly like others mentioned I typically do revenges from the bottom of the watchtower list going up. I did a revenge against someone, lost, and later succeeded. However, my successful revenge was counted as a raid because his original raid rolled off my list. He then subsequently revenged my revenge because it was taken as a raid.
While I get why this happens I don’t think it’s fair. If I lose my initial revenge I have two more revenges available. By this point their original raid is rolled off and if I revenge now it’ll be counted as a raid; in fact if I were to close this screen I wouldn’t even be able to revenge anymore because their original raid will have rolled off. So the fact that the revenge lost screen allows me to revenge at this point would be a bug.
I think it could be handled by either
Count an attack as a raid based on how it’s initiated: either from the revenge button from the watchtower list or the revenge lost screen.
Count an attack as a raid based on whether the attacker’s raid is in your watchtower list (how it seems to presently be). In this case disallow a revenge from the revenge lost screen since it would be interpreted as a raid, or allow it but show a warning the revenge will be counted as a raid.
Personally I would opt for option 2 since that seems fairer. It would preserve game mechanics of allowing to revenge but not if I wait too long.