I recently received my M11 Plus which I am very happy with but the FiiO app has issues which I am not experiencing in the USB Audio Player Pro app which has all my music sorted and listed perfectly.

In Artist, a few categories end up split in two.

Below you will see in the first two screenshots that ELO appears twice and in the UAPP app it appears correctly once. Another example below those two screenshots show two Various Artists folders in the FiiO app and correctly as one in the UAPP app.

I am using Version 3.0.5 of the app. 

I have rescanned a number of times and keep getting the same errors.