Legs Get Crushed Down During Walk Cycle

So I had the exact same problem, although mine actually looked worse. ( I had 9 characters looking fine and the 10th not working)  I contacted my person at Adobe and he diagnosed it. It was one tiny little check. Ramon in this e-mail is the one with the issues. Tiffany doesn't have those issues. That completely changed everything.

"Oh, geez. It's even easier than I originally thought: the top level node where the Walk behavior is attached (called Poses for the Ramon puppets) is not warp independent, but Tiffany's top level group is warp independent. If you toggle the crown column on for Ramon's Poses group, the shrinking behavior stops.

The centering of the scaling is just due to Tiffany's top level origin handle being placed at her feet instead of its default (more centered) location. The fixed pins on the profile views don't matter for Walk, because it also pins the feet, but you might need them if you trigger the profile views for standing looking left or right.

Anyway, hopefully that helps!"

Ok, so I found out that my legs were not attaching to the body, so the legs were shifting up on the body. Earlier in the process I had set the Attach To for the legs to Fixed points I placed on the Body.

I set it back to Auto, which made it so the legs now attach properly to the Body.

However now I'm back to my original issue of the puppet shifting down in the frame entirely, so the feet don't line up along the same plane. I'm not seeing this issue with the sample puppets, so I'm not sure what I'm missing.

i don’t know the answer, but what I would suggest trying is adjusting relative position of hips and waist and origin etc. if head and neck handles are too close you get weird warping. Maybe it’s similar. Also try experimenting with walk strength settings. If you learn sometging, please share here!