Unfortunately, It is possible that your document has corrupt field codes in it. We have a FAQ on our web site that gives the steps to remove all of the field codes and clean up the document. You should first make a backup of your Word document and then follow the steps in the FAQ at:
You may have to reinsert any citations that do not unformat in the format of Author Year and Record Number.
If you need additional help I would contact Technical Support directly.
1-800-336-4474 or
https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US