Arelith

I've run into situation couple of times where picking up a corpse and then dropping it results in permanent reduction of speed (character can't run anymore, and keeps walking as if encumbered), if the character has low str (10 or so).

Would be nice if somebody looked into it or posted a workaround. Relogging is the only way to fix it that I know.

Have you tried toggling -alwayswalk
That sometimes fixes similar issues.

Popping into and out of stealth works for me too.

This seems to be happening with things other than corpses and naturalwalk/stealth does not fix this. Only relogging.

Basically, if something briefly brings your character above weight limit, and then drops you below weight limit, but close to it, the character can no longer run.

I've seen this as well and wither a Stealth/Unstealth toggle works or relog.