cite="yes" RIS translator issue

When I attempt to “save to zotero” when visiting a wordpress page with a zotpress generated bibliography (cite=”yes”), only citations with a DOI are saved.

Here’s a sample page to illustrate the issue:
http://dh201.humanities.ucla.edu/2015/bibliography/

I noticed similar behavior on the website linked in the support topic “DOI showing up arbitrarily”:
http://www.backonpoint.com/library/mind-body-research/

Is this a bug or a feature? And is it strictly speaking a zotpress issue or is it a problem on the Zotero side of things? (Or is it user error?)

https://wordpress.org/plugins/zotpress/