About that combo, looks like the slope affected it. That's why I was able to do it. If you are on the higher ground, that combo is possible.
So, a correction to my correction. I figured out what's going on here.
The reason that combo hit before is because of my training settings. This is what happens in each of these settings.
3P > 64P > K,H+K > 9KK > K,H+K (91 damage)
mid kick + no SE = combo does not work
mid kick + slow SE = combo does not work
mid kick + fast SE = COMBO WORKS
mid kick + fastest SE = combo does not work
So that's kinda weird that the combo will work on a flat stage if they SE and it is a fast SE.
And with this combo, 3p > 64 P > K,H+K > 6K > PPK2K (90 damage)
mid kick + no SE = COMBO WORKS
mid kick + slow SE = combo does not work
mid kick + fast SE = COMBO WORKS
mid kick + fastest SE = combo does not work
Both combos will always work though if you're on the high ground of a slope.