User Event Script Does Not Fire for Webstore-Created Sales Orders

I have a user event script that processes new sales orders with an after submit function.  I developed this script using the debugger a few months ago and then released it.  It has been working fine for sales orders that are created both using the Netsuite UI and our Netsuite webstore.

Yesterday, I started working on adding some extra functionality to the script.  The first thing I did to begin my new development work was to change the script's deployment status to "Testing" and try to step through the script with the debugger.  I ran the script in the debugger and then created a new Sales Order using the Netsuite UI.  When I saved the Sales Order the script's after submit function was called and the debugger stepped into the script; exactly what I would have expected to happen.