Why does my Nokia Lumia 520 phone keep going back to 10 instead of staying at 30?

[Windows Central Question]

why does my nokia lumia 520 phone keep going back to 10 instead of staying at 30

it was ok awhile ago

 

[xandros9]

Re: why does my nokia lumia 520 phone keep going back to 10 instead of staying at 30

I don't understand.