You don't even have to roll or wake-up attack, though, you can just start standing up while the Ground Pound goes off... it'll whiff right through you.
And the only reason f+4,1,3 > Ground Pound works sometimes and not others is because either I time the Ground Pound slightly differently or the opponent's timing is slightly different as far as I can tell... I have the opponent set to always jump and as long as I always buffer the Ground Pound so it comes out as early as possible, it always whiffs because the opponent is in the correct portion of their standing up animation to avoid it, but if I delay the Ground Pound a couple frames, it always hits because the opponent is already past that point in their standing up animation. It seems to have no inconsistency. I also tried using the record feature in the same fashion as Riu, but the playback feature always causes the Ground Pound to whiff unless I do it very late... I think that's just the playback feature messing up, though. I don't think the bug affects anything but blockstun.
