askvortsov Although tbh I'm not 100% sure what the use case is for letting people see the inbox tag and all discussions within the inbox tag?
That's the standard setup for a Byobu Inbox. In addition to the permissions granted in the admin panel, the participant status for any private discussion must be met as well. If you want to allow anyone to participate in private discussions, that's the normal setting for the admin panel.
It seems, your extension doesn't properly check for the private state of private discussions, so Byobu and Flarum Help Tags are simply incompatible at the moment. I guess your extension together with Byobu will cause big trouble even without a designated Inbox tag.