Cross-major registration is actually that the major you are applying for now has little or no connection with the professional subjects you studied in university. This is a normal reason. After all, not everyone can find a job that suits their major, and then they are likely to learn knowledge at work, which will lead to cross-disciplinary registration, which is also allowed.
However, there are some limitations. For example, military, police and medical majors can't apply if they haven't studied the corresponding majors before, or they are engaged in jobs that don't correspond to them.