We have one document library that started showing the error ' An item with the same key has already been added. ' for all files when trying to edit the metadata of the file.
I can't seem to find any occurences of the problem on the web. Has anyone here ever encountered the problem? If so, how do I fix it?
Additional information:
- SharePoint Online
- The Document Library has Document Sets
- Problem occurs for both properties of the document sets and files inside document sets
- When using 'Quick edit' the properties can be edited
- No duplicate files
- No document approval flow
- Besides the document set, it's a vanilla document library
