Hardly any album that I want to add via mobile will show all of its songs. On the desktop application, the same albums usually display perfectly. So, I'll try to repeatedly add them there and refresh on mobile to double check. Some albums won't even let me visualize all the details, though. (It's a very unfortunate pattern to discover in this process that Amazon is missing several albums from some of my favorite artists. Because even if I have those albums downloaded, I can't integrate them).