A bit odd, indeed, but not impossible at all… if it was closer to 30/30, it would have been nothing unusual. But when you lost18 cups, your enemy won 43 so winning only 18 by defeating him on strike two, means that, somehow, your cups count got reversed, so if you had lost instead of winning this time you would have lost 43 this time. There are some factors that might lead to this kind of situation, like your opponent being raided by other enemies at the same time as your first attack and losing a bunch of cups before your second strike.
If an opponent beats me out of 18 cups, the raid mechanism would have awarded me 43 cups had I won, instead. Winning an immediate rematch means I should have won 43 cups plus.
Don’t think I am adking for the extra reward; rather, your mecanism needs to be checked
First, if you lost your cups go down and your opponent’s go up. If you raid him immediately with no other change the cup difference will be larger (since you only lost 18 your cup total was lower), not the same.
Second, to raid immediately your opponent must be high enough to be attacked when online. That being the case they will likely be attacked even while attacking you. They could easily have dropped in cup count while gaining 18 from you.
Since your revenge only gained 18 cups it sounds like the difference between you flipped. Were they using a cup dropping defense?
Third, chill out and relax bud. If you don’t want to learn then why ask?
If you believe it is really a bug, then you will have to submit a support ticket to SG. But generally, if it does not happen to affect the majority of the players (in which case, usually there would be many players complaining about the issue on the forum), it will not be regarded as a bug.