I had another bizarre issue with this 'Premium' phone yet again the other day.
Had the phone on the kitchen work surface and I was just below looking in a cupboard, and I 'THOUGHT' i heard my text notification, but wasn't certain. So I checked my phone and yes there was a text.
Don;t ask why I did, but I sent myself a text and low and behold the notification was sooooo quiet, I could barely hear it.
Yes, I did check all the volume settings and they were on MAXIMUM!
Tried several texts and all the same, incredibly low volume on the notification.
I did a restart and it did increase the volume on the next batch of texts I sent myself, but it just doesn't seem as loud as it normally is...(believe me, it normally startles people!)
I'm losing track of the number of issues I'm now having with this phone!