Tested with TV shows. Episode description is shown for unwatched episodes when the new OSD header is activated. The expected behavior is to hide this information for unwatched episodes, which is how OSMC (and other Kodi skins) behave during episode selection.
They do during episode selection aka the library. But the setting does not affect the OSD of any skin AFAIK. In fact, on the skin side the Kodi setting doesn’t have to be respected at all. The info texts are simply not passed to the skin, if it’s active. It seems that Kodi doesn’t want to hide the plot texts in the OSD.
So you’re saying it’s a Kodi core bug, not an OSMC bug?
Either way, I have disabled the OSD feature completely and won’t be able to continue testing it, because I don’t want it to keep ruining TV shows for me.
One could call this a bug… Or it’s at least not really straightforward considering that all other plot text would be hidden.
But it should definitely not be something our skin is responsible for. It’s just picking up what Kodi is passing on to it. And if the option is enabled, it only gets the hidden text message for most plot text. Just not this one, it seems. Nothing the skin can do about that.
EDIT: Checked with Estuary as well… Same behaviour. The setting doesn’t take effect in the video player info dialog.