So I checked what your Library is returning and it doesn’t appear to include the ‘included in plex’ flag, so at least there’s not a bug on the client side as far as I can tell. Considering you mentioned you’re syncing with Plex though, I’m unsure if perhaps it’s something specific to your configuration (and a bug with setting that flag). Do your settings on the website seem to be similar to those shown in the original message of the Plex Beta thread?:
I know you’re saying having a setting would essentially solve it (for you), but it seems like a workaround rather than a solution, eg. I’m not sure it really makes sense if it means even item’s that you don’t have access to would show up with an ‘Open in Infuse’ action.