No way you'd still think that if it was the other way around like.
I don't think it's biased to say I wouldn't. Granted, I'm not watching on the best TV at the moment, but those replays don't show anything in it. Dummett goes to ground, gets the ball, and all I see is Mahrez tripping his own foot up with the other with no contact from Dummett. If that was us, I'd be gutted we didn't get a penalty but I'd say fair play to the ref.
Dummett doesn't get the ball like, he pulls his foot away before making contact with Mahrez or the ball. The potential foul happens when their knees collide