The mobile app is functioning properly. What you are seeing is RM's model for storing sourcing information. Which is not to say that even with RM's model for storing sourcing information, RM perhaps could display sourcing information in a fashion which is a little different than the way it stores it.
RM stores the information which is displayed in a footnote sentence into two parts. Part of the sourcing data - usually the left hand part of the footnote sentence - is stored in the Master Source. And part of the sourcing data - usually the right hand part of the footnote sentence - is stored in the Source Detail. Sometimes users refer to the "Master Source" and the "Source Details" respectively as the "Source" and as the "Citation". Not everybody agrees on the best terminology. I personally prefer to think of the footnote sentence as a whole as the "citation".
Be that as it may, when you look at the Source List view in the mobile app, all you are going to see is the data that is stored in the Master Source. So the app is working as designed. The same thing is true with the main RM app on the desktop. When you go into Lists->Source List, the only data you can see is the data from the Master Source, which is exactly the same way the mobile app works. The difference with the main RM app on the desktop is that you can click on Print and see a printed report of all the citations which go with a particular Master Source. But such a report can be dozens or hundreds of ever thousands of pages of pages long. That wouldn't work very well on the mobile app.
That being said, I think that on the main RM desktop app, a better way is needed to display all the citations associated with a single Master Source than just making a large printed report. Perhaps some sort of live and scroll-able list of the citations could appear within a frame on the screen. You would have to worry about the list being long. But things like the Source List itself and the Place List, etc. can be pretty long, and both of them are live and scroll-able within a frame rather than being a printed report. If something like this were done in the main RM desktop app, then perhaps the same thing could be achieved in the mobile RM app.