It sounds like your authors may be entered incorrectly in your records. They must be one to a line. Otherwise endnote interprets the authors all on the same line as one name, despite any punctuation to the contrary.
updating the reference – (if I think I am right, that you have two simultaneous threads on the same subject???) might fix this if it can find the correct match- as it will replace your authors with the author list, one to a line.