Don’t mind me, I’m a smartass, no harm meant 
Well then there may be a bug there. I got my 30 seals with one loss in the arena yesterday.
No bug. Currently you get 30 seals for 8 wins and either zero or one loss.
Edit: Apologies for accidental necro - even us Regulars can get sucked in by the forums presenting old as new… 
Then it is not a perfect run if you have a loss.