Pretty please, tell me someone has a solution for this. I've figured out how to update managed metadata in SP lists (most of the time - it's a little temperamental), but I absolutely cannot get those exact same columns to update on a library. This is driving me nuts. Please help.
@leighburke Yup, using term GUID. It's super weird that I can update the site column on a list but not on a library. I've contacted Nintex support and they are helping with troubleshooting - I'll report back once we have an answer to the puzzle.