My Samsung A50 restart spontaneously, what is responsible?

[Mudegg]

there is a setting that would restart your phone occasioanlly to maximise performance. But it would only do it when not being active, dunno if it's that?

[BandOfBrothers]

It could be several issues ranging from software or hardware issues to a downloaded theme, battery monitor apps etc or apk files @Shinajames

Ensure your phone us up tondate with its software and all your apps are updated. 

• Try >

Safe Mode  > https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/ turns off downloaded apps and themes etc which may highlight an app or theme that's causing conflict. 

Clear Cache Files from the phone's System Partition Section  > https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ You may need to insert your earphones or hook upto a powered On Laptop or use a Tv's USB Port to access the Clear Partition Section. This may help with lag or stutters as this clears the phone of old/unused or broken cache files.There is also a Repair Apps option in the Menu System too. 

As a last resort back up and factory reset.