You may need to check the setting in the style you are using for Ambiguous Citations:
In EndNote you can go to Edit > Output Styles > Open Style Manager > locate the style you are using > Click Edit > go to Ambiguous Citations under Citations > here you might need to uncheck the option for Include the author initials or full name in citation > go To File > Save As > (EndNote will not allow you to change the existing style in EndNote but will always apply the change to a copy of the style) Click Save to save the changes to a copy of the style > close the style window.
You would then update the document to get these changes to show up.
If this does not help then please contact Technical Support directly
1-800-336-4474 option 4 then 1
or
https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US