I found two tied guards in the woods. They were guarded by Cumans. After killing the Cumans I proceeded to untie the guards. After untying the second guard I was unable to move at all. I then loaded an earlier save and still could not move.
After restarting the game I was able to move again. Then I proceeded to untie the glitched guard again and the same thing happened. I took a screenshot of the guard.
I guess I will leave the guard tied until the bug is fixed.