To make the app sort your list the second you walk in the door of the store and the app has received your location, it utilises “caching” of the sorting received last time you visited the location.
However, it can happen that the app received no sorting, e.g. because you had been visiting another country and forgot to change your settings when returning home.
This means the app now has an empty sorting in its cache, and hence no sorting appears at location where it used to work.
The fix is to log out of the app, which will clear all caching, and then login again. You should not need to delete the app and reinstall.
