Import Users Failing
 

Trying to import one 3.8.4 forum into another 3.8.4 forum. During users import for "Would you like to associated imported users with existing users if the email address matches ?" I select yes. Unfortunately instead of associating imported users with existing users if there is a matching email address ImpEx throws an error:

Invalid, skipping. Failed on :

What do I have to do to get this to work as advertised?