I noticed this first with message notifications, I generally turn off all audible notifications, and it’s dinging away. Also playback pause and resume appears to be hit and miss in B3, this rather compounds the issue as not only do you get a notification you didn’t ask for, your media playback pauses and might not come back. Radars filed, just #BetaLife experiences as we all expect.
Text message notifications have been flawless for me and so has media playback - at least to this point...