I see the same issue with v2.6.1. If you open a published page, change the status to pending review, make edits, then save — your “published” version is updated with the changes you made, even though you haven’t “published” since making the edits (the status is still “pending review”).
I’m not really sure how the Pending Review status is intended to work in WordPress. Are you supposed to be able to take a published page and change it to pending review?
