Many makers close apps on their own to save battery. KidPair recognises the phone's make and shows its special settings under the main list: autostart, “don't close when clearing memory”, pinning in recent apps. Turn them all on — otherwise the phone may close KidPair and the rules stop working.
Each setting has an “Open” button (straight to the right screen) and “I did it” — for settings the phone doesn't let the app check.
Xiaomi, Redmi, POCO: “Ultra battery saver” closes KidPair and switches it off in Accessibility — rules, limits and the map location stop working until KidPair is turned on again. So the list has a step “Remove ‘Ultra battery saver’ from the shade”: pull the shade all the way down → the pencil (“Edit”) → drag the “Ultra battery saver” tile down to the unused ones → “Done”. If the mode is switched on anyway, you get an urgent notification at once. When it is switched off, open KidPair on the child's phone and turn it on again in Accessibility.
Pin KidPair in the recent apps list (the padlock on its card) — then “Clear all” won't close it.