I have seen a number of complaints about the Mudita Kompakt suddenly silencing text notifications (among other sound notifications). For my own part, I have found a pattern related to the Meditation App. It is always after using the Meditation App that my sound notifications are silenced. If, after using the Meditation App, I enter the ‘Manage Apps’ submenu and ‘Force Stop’ the Meditation App, then move the volume slider up and/or down, there is no silencing of sound notifications. If, on the other hand, I close the Meditation App after a period of meditation and DO NOT ‘Force Stop’ the app afterwards, my sound notifications may be silenced indefinitely.
I share this in case it helps anyone trying to track down the source of the ‘silenced sound notifications’ bug/problem. I believe it is a failure of the Meditation App to properly restore sound notifications after it silences them during a timed meditation period. Somehow, I think it is continuing to suppress them even after the meditation period ends and the app is closed.
I hope that helps.