When you duplicate anything that has IX2 interactions, all the interactions get renamed to the duplicated class rather than remaining associated with the original class they were assigned to. It seems logical that the duplication of a class should duplicate all the interactions as well.
How it could work:
WEBSITE ELEMENTS BEFORE
Class: box1
IX2: move_box1
user proceeds to duplicate box1, and names it box2
WEBSITE ELEMENTS AFTER
Class: box1
IX2: move_box1
Class: box2
IX2: move_box2
Best,
Christopher