I just had this same issue, exporting from the notebooks page, my main book of about 350 notes.
So after seeing this I tried just going into the "all notes" view and selecting the ones I was really concerned about backing up, about 121 notes, and they went just fine.
So this means there is what? Searching for notes in this manner was a one kick step for me but could be quite tedious depending on where the wrong zeros are at.
Some miscommunication between OSX and Evernote that needs mending? Seems like it's probably more than just empty screenshots but I'm no coder.
Additional information: I'm still on Sierra. I don't trust Apple anymore.