I have a new P9P XL (last week) which i've been using but having some issues with Ringer and Alarm sounds. I re-flashed earlier today using the web-installer. Verified the boot key hash.
I have not configured any settings in the initial set-up, the phone has a sim card installed and can reach the internet via mobile data. Everything is default, as it is out the box. Owner profile, Modes like Sleep and DND are disabled. Media playback and voice calls work fine without issue.
I will note if I have a Bluetooth speaker or my earbuds connected, I can hear the ringer sounds so it appears to be related to these sound channels being played through the internal speakers.
The only time the ringer, notifications and alarm sounds play is after the initial unlock after booting. As soon as you lock the phone and wait 5 seconds, even after unlocking, they stop playing.
If you reboot the phone, the ringer, alarm and notifications work until you lock the phone and wait 5 seconds. If you keep the screen on and unlocked with something like the stopwatch in the clock app, it will work even after 10+ minutes until the phone is locked. After locking and unlocking, the only way to get the sounds to play again is to reboot.
Most of the previous threads I've found either on this subreddit or the GitHub issues tracker have been configuration related but I believe this might be a bug as using an 'out of box' config with nothing changed.
Any help would be appreciated as I can't really use it as my daily phone if I can't hear it ringing.