Hi,
I'm not sure what machine or finisher you have but it is most likely that what you are trying to do is out of specifications and that is why the machine doesn't follow it. I've seen where using heavy cover stock can remove stapling selections on some products.
Hope this helps explain what's going on. If you have questions regarding this you should refer to your specific printer model's specifications.
Regards,
KenB-Xerox
Having problem with mixed media and stapling. Set-up on text stock and get the staple right on the fold, but when you add a heavier cover stock to the text the set-up for the staples doesn't get used.
Know matter what number you put in to move the staple it never move