This may not need a video! i was baffled until I noticed that foots are children of the calfs
If the foot bone is the target for an IK constraint, it can't also be a child of the bones constrained to follow it. I'm surprised A:M let you do that, that should be a circular constraint error.
The foot bones need to be higher I the hierarchy at either the Root or Pelvis level. I know I had it working in the video so check that video for how I had it.
Delete that whole leg constraints relationship, fix the heirarchy, then redo the Leg Constraints relationship.
Then see what you get.