That is a huge bummer and I still cant figure this out.
Here’s a video showing the problem as well as pictures of the character state (Hit Stun Air) simplified to do nothing besides play the sprite and add movement and the add movement code. I added the branch after Add Movement Input to try to force the character past velocity x=0 but you can see sometimes it still gets stuck there. Sometimes it does not… 
The same result happens without that branch and everything after it.
In the video I am holding left the entire time the character is in hit stun without variation.
