After using the "go to unread comment" feature on the complete review dialog, "the "From" and "To" revisions on the file revision slider are swapped, meaning it shows added content as removed and vice versa. Sliding the "From" marker back in front of the "To" marker fixes it, but it's confusing for a moment.

(Version:3.6.4 Build:20150123083607 2015-01-23)