I was having a similar problem with Halo, my 4 mo. old female. I've been gating her and TJ (8 mos) in the bathroom. She'd do the same thing; poop and stomp in it, getting it all over the place and on her too!
I started putting their beds up next to the gate, now they go back to the pee pad to poop. They don't won't stinky poopy by their beds.
Give this a try, maybe it'll work for you too.