I’ve been using Endnote before getting my Mac, and it was possible to right-click on a reference in the Endnote list and paste it with the ‘copy formatted’ command on a word doc. (in order to write the list of references used in a chapter, for example) With Endnote X3 the same action only pastes the surname of the author in brackets!
Do other Mac EndnoteX3 users see this? If so, then it needs to be reported as a bug in the Mac version.
Can you copy it from the preview window? Of course that is a one by one solution.
In the case of “copy formatted” several at once, in the meantime, I would insert them into a separate document, select the refs, unlink the fields (shift+cmd F9? on the mac?) and then paste them into your other document.