My note 10+ ringtone keeps changing back to default after restart, recently bought a new A12 phone, I did a factory reset and this phone also happen same issue, ringtone changing back to default as well... Alarm become ringtone if I set Auto restart on the phone since day one I bought.. too many bugs... I email to Samsung support and problem unsolved till now.
I have the s21 and mine does the same thing. I change the ringtone then it reverts back to the default for some reason. I have tried all of the settings and cannot figure it out.