The tutor asked a wide range of questions in the second interview, and the questions about reference books were only a part. For interdisciplinary students, the tutor may be interested in your original major, so you should also be prepared. There are also some tutors who want to examine students' understanding of the frontier of this major.
There are many complicated ways to ask questions about the recognition of this major, so that students can fully understand all aspects of knowledge related to this major as much as possible.
Will the teacher ask professional questions during the second interview?
I can't give you a definite answer, but some institutions will ask, but others won't, because they have all been inspected in the initial test. Although such institutions will not ask professional questions, they will also know your major.
Questions, such as how much do you know about professional frontier issues? Knowing what theory and so on is not a problem at this time, but he knows from other questions that there are many traps, so he should be actively prepared. The questions asked by the tutor are all purposeful.
Yes, so the second interview needs you to know more about it.