I noticed that when running/walking down the stairs in many houses/buildings, I've seen the right foot glitches through the stairs, but have also found that the left foot also does this but it is not as common and very unnoticeable. Walking/running up stairs doesn't seem to have an issue.
I've included a video to show what I am talking about and also the houses I've tried it on. The last house shows it the best since the character was limping. It doesn't seem to matter what condition your character is in.