I cloned the storefront and in the cloned version, "Act on Behalf" is working.
please clarify. Did you created new additional store inside your Abantecart (multistore feature) or just copied your instance of application to another host?
I didn't create a 2nd store inside AbanteCart. I copied the instance and placed it in a subfolder at the same host.
Now, when I attempted a upgrade test on the clone to move from version 1.2.2 to 1.2.3, it failed. (I won't mix the issues here improperly, but will post another topic.)
Anyways, AbanteCart is an awesome shopping cart and I know this will be resolved in due time.