DUPN function duplicates the top N elements of the stack after having consumed N which is on the top of the stack when calling
DUPN duplicates the references of the N elements on the top of the stack, it doesn’t copy the elements.
If you apply
DUPN to a GTS you will have two references to the same GTS object on the stack.
If you want to make a deep copy of a GTS, i.e. if you want copy the content and not only the reference, you can use the