Hi, natyjay!
Not to worry, this is functioning as intended. When you cross-listed class B into class A, think of class A as "sucking up" the enrollments of class B. You should see those in the People tab of class A now. As for the content, that is normal. So, why would you cross-list classes?
Say you have two ENGL 101 classes. You're going to teach them the same way, and you already have all your content in one class. You cross-list them so that the enrollments are combined into one class. As for the other class, class B in this case... you don't need it because you already merged the enrollments into one class. Does that make sense?
This guide will tell you more about this. Oh, and to deCross-list, you just go into class A, click "Sections" and find the section (class B) you cross-listed. Click that section, then click "decross-list" to undo this. Your content and enrollments should be restored.
Please let me know if you have any other questions!
Nathan