Since many months (and 2-3 Android Updates) my S20+ OS behaves definitely out of specification in context of "Screen Timeout" setting.
Despite me setting this value to (for example) 30 sec, Android itself randomly changes this setting to "not existing" value (!) - the list of available options for this setting starts with "empty/NULL" value "()" instead of "1s" and its ratio button is checked.
I can set 30s again and... after few minutes/hours it is set back to out of specification value NULL.
After setting its value to 30s the list of options is updated and starts with "1s", but after automatic change to NULL, the same list for Display Screen Timeout has one more value to chose - > " () " (and it is chosen).
About half a year ago when it started, it was rare anomaly, usually after device restart OR going into "Flight Mode".
But with last Samsung S20 update (August 2023) now this resetting anomaly started to be tricked every few minutes 😞
I set 30s, it is stored, I can go back to Settings and see that my 30s choice is still valid, leave the phone for a few minutes or use it for few minutes and ... BUM! - the setting is reset back to "NULL" 😞
I can not catch any pattern/logic to identify what event is causing that reset but it is now happening many times per hour.
After being advised by Samsung Support Consultant to perform cache partition wipe out - I did it twice with NON effect on this anomaly 😞