Hey, I had the same issue and the cause in my case was a change in the skeleton using the setscale command (I made my character taller). If you are using a mod or commands that changes the skeleton you should try reverting back those changes and that should fix the glitch. I hope to have helped resolve your issue.
Play as a Dragon SE animations broken
in Skyrim SE
Posted
Hey, I had the same issue and the cause in my case was a change in the skeleton using the setscale command (I made my character taller). If you are using a mod or commands that changes the skeleton you should try reverting back those changes and that should fix the glitch. I hope to have helped resolve your issue.