Yea because you shouldn't have even had three score because you only won 2 battles.

But the match should have ended in a draw. The opponent got 3 points and so did I!

Hello! Could you please report this issue to our Support team via this link: https://plrm.me/arena_support or email them at: [email protected]? Including this screenshot depicting the issue would be the best, as it helps us to investigate and resolve the problem faster! 

when you have a draw it counts as a loss. There are only 2 recording for battles wins / battles. There is no draw section. if you have a draw it does not count toward your wins but count as a battle which decreases your win ratio. It has been asked before why draws count as losses. for the past 3 years they have been looking into and to look out for future update. :/