Is it intended that you cannot mark a file as "viewed" if the left revision is not the base revision, but the right revision is the latest? The button is disabled with "marking as viewed is only supported when viewing PR's latest version", but I do view the latest version on the right side. I just do not compare against base, but against the state from last time I reviewed.

Hey! I'll check with the team to see if this is the intended behavior and get back to you!