Hi,
If you are using "PlayerPrefSetInt" and "PlayerPrefGetInt" these values will persists outside active session and you can close the app the data will persits.
If not, you are likely setting the value to an unexpected value before closing the app.
you can test this in Unity Editor, simply stop playing, and start playing again, the playerPrefs will work the same within Unity and Editor and on Mobile.
Bye,
Jean
Bye,
Jean