When you enable the Hide items which are in collections option it breaks the sorting. If you are using the web client and click on A,B,C… etc you wind up somewhere completely different. For example if I click on M it find myself somewhere between R and S. On the Mobile App scrolling down the list shows the Letters and if you stop on M there is will take you to the same place.
Known issue. It will be fixed in a future update.
Great. Thank you for the update. Just wanted to make sure it was out there.