Hello!
We have faced such a problem on our Confluence Server 7.11.1.
When we disable the system mobile plugin (Confluence Mobile Web Plugin), so in-app notifications are also turning off (because of Workbox - Host Plugin is disabled when I turn off the mobile view) (I don't know why).
It seems they are tied to each other. But we need notifications and do not need the mobile version.
What can be done in this case?