References corrupted


I have been having this strange problem for a few days now across every document I use.

When the references are added to the document with a space in-between everything is fine and the field codes fill out properly. Please see attached examples

As soon as I try to join the references together to be treated as a grouped reference it deletes all the field code information and replaces it with a blank field code {ADDIN EN.CITE }

This means when I close and reopen the document the references are broken and I get an !!! INVALID CITATION !!! error. This has happened to around 40 citations in my document and I would very much like to get it fixed if possible!

Is there any fix for this?

Thanks for your help!