Those animations look like edited motion capture to me. What does that mean?
It’s motion capture that is tidied up by a artist. (But I could be wrong)
With motion capture, you will find ‘pops’ (most of which are cleaned by an artist) however, when it’s captured from a real person the body mechanics come for free – if that makes sense.
In the one that you pointed out can you see that the both knees are different? The Right knee overshoots and pops before the contact where as the Left knee does not.
This type of pop is obeying the body mechanics.
This happens on a lot of people’s walks – depending on the style of walk. (walk cycles are really complicated, if you didn’t already know haha)