I have a very strange, intensely annoying bug on my Skyrim in the most recent patch. Whenever my walking speed is reduced while I am standing still, I'm completely immobile until I satisfy the conditions to move at normal speed again. What this means is the following:

If I draw a bow from a standing position, I can't move. If I draw a bow while walking, I can move normally (slower than normal walking speed). If I pick up enough extra weight that I am encumbered, I am immediately immobilized, since it's not possible to grab inventory while moving.

I have tried disabling all mods, to no effect. I tried removing and reinstalling my entire game, and after a brief period of working normally, the game has once again reimposed the bug, after a few minutes of play. Has anyone else run into this behaviour? Is there a fix known? Is this something Bethesda has acknowledged? Can anyone help?

are you suffering from a disease that lowers movement speed as well?

its possible they are stacking, macking you immobile

No, for a couple of reasons. Number one, I tried a new level one character and encountered this same behaviour once I got my bow on the way out of Helgen. Number two, my main character is currently a vampire, which makes contracting diseases unlikely.

Do you have any animation replacers installed?

Not so far as I know. I have Ethereal Elven Overhaul, the texture packs, and Hearthfire and Dawnguard, and that's pretty much it. If that makes some animation changes, it's news to me.

Have you installed any in the past? There is a chance that the animation files could still be in placed folders. (ie: something like "~/Meshes/Character/Male/*.kf" or something similar.)

Sorry, I'm at work ATM so I can't see the file and folder structure of the Data folder for the time being. You may try searching for .kf files to see if anything is there. The default Skyrim animation files should all be packed into the BSA archive files.