+1
Google Pixel 2 on the new Android P v9. I can't stand the sound of the outgoing notifications and I haven't found a way to successfully make it stop..
Furthermore, it appears as I though I get the occassional 'ghost' notification - maybe a delayed send? I don't know but I'd love for...
I have been having the same issue with my s7 for months. I don't use YouMail so I don't know what the culprit is. It seems to happen when I listen to audio over bluetooth a lot.. ugh it is so annoying having to restart my phone so often!