After using the content and structure system to copy documents from one site's document library to another, the document properties fields that are set to accept multiple metadata values from our taxonomy are no longer accepting these values (either a single value or multiple values).
As part of the move, SP2013 added new columns to the table for every multi-value metadata field. (i.e. "Product" now has a companion column called "Product_0" which is a multi line text field). I understand this happens due to the method of transfer using content and structure.
So, when a new document is uploaded to the doc library, I can input all the other classifications (i.e. drop down options, single value metadata columns), but the Multi-Value metadata field does not save. I can fill in the values and no error is generated when saving the changes, but when I go back to the table view, the values I input are not saved. When I re-open the document properties menu again, the values are not saved there either.
If I use "quick edit" from the table view, I can edit the columns and the values will be saved correctly.
How do I get the document properties page to work as expected again allowing users to correctly complete the multi-value fields and having them saved to the doc library?