bugs

I was fighting granswhore and I won with 33% hp left and it gave me a loss and lose kudos and a record of one loss

You most likely exceeded the time limit. Forgot what the threshold is roughly, but it counts as a loss when you go over.

Fellow endfielder?

Believe its around 4 Minutes

Iirc, the limit is 300 attempts. If the attacker isn't able to defeat the defender, the defender wins the battle.