On my Note 9, since applying the April 1st security patch, my notifications can no longer be silenced (updating to May version did not solve this). No matter if my phone is set to mute, vibrate, or do not disturb, notifications will cause the default tone to play at full volume. I have not installed any apps since the update that could be cause of this, nor have I changed any other settings. I can go into the notification settings for each app and set them as silent, however doing so for 300+ apps is tedious and an unreasonable solution. Anyone else encountered this or have a solution?