Suggested fix (unconfirmed): Disable or remove the Better UI inventory mod. If that does not work, verify your game files multiple times until no corrupted files remain and restart your PC.
Suggested fix (unconfirmed): Remove all outdated mods and delete any leftover mod directories with older dates. Then, verify your game files through Steam and reinstall only the mods that are compatible with the new DLC.
Suggested fix (unconfirmed): Buy a replacement Nibrak Cloth Armor from Tina's Tailor Shop in Hernand. Check vendor inventories or wait for a patch if you lost upgraded stats and socketed gears.