I had that problem yesterday as well. I found that for some reason the game created new live folder, inside the existing Live directory. No idea why, but the game is now pointing to E:\Documents\Elder Scrolls Online\Live\live.
Since that directory didn't exist, it created it and created new files for user settings, add-ons, etc. Copying all of the files from the Live directory into the newly created live directory solved the problem. I asked around in game, and nobody else had this happen, so it may just be my client that's jacked up, but it's worth looking at to see if that's what's happening to you as well.
Update.
I looked in the previous OneDrive folder path for when I had OneDrive enabled (C:\Users\<username>\OneDrive\Documents\Elder Scrolls Online\live. It exists and a copy of the addons are there. No change.
Any other ideas? Is there any way to tell what location the game is actually using? Is there a way to specify the location?