Re-enabling “watched / unwatched” flag in Confluence

Apple TV2 (Software v4.2.1)
Operating System Darwin 10.4.0
Kodi v14.2 Git:2015-03-26-7cc53a9-dirty

About a fortnight ago the watched/you are midway through watching/unwatched flags all vanished and haven’t returned.

I’ve found lots of people asking how to turn this feature off, but no one ever seems to have the issue where it turns itself off against the request of the operator.

Can anyone explain why this stopped working and how I can restore the feature?