AG@GOUD12 , via OnePlus 7 , Oct 22, 2020 : I few weeks ago I noticed that my alarms aren't playing any sound it is only getting vibration.i am tryed to change the settings but there is no use. The alarm itself does go off but it only vibrates which doesn't wake me up sometimes. I've also noticed that notification sounds in general have issues. My default text notification sound sometimes reverts to the default for the phone. Seems to be a re-occurring issue. For your reference please refer screen shots
the_o2 , Oct 22, 2020 : Clear the storage data of the clock app and restart your phone once and see if it fixes the issue
arshad_viii , via OnePlus 7 , Oct 25, 2020 : Clear the storage data of the clock app and restart your phone once and see if it fixes the issue
Basudev7 , via OnePlus 7 , Oct 31, 2020 : This was a bug.. it will b solved after the next update. No worries