Overlaid Orders
An overlaid order is an order that gets replaced (in full or in part) by a completely different order.
It's caused by a race condition in FF4 that happens when trying to use FF4 too quickly. We're taking steps to eliminate this problem by adding "governors" to slow things down where needed. In addition, we're adding checks to make sure an overlaid order does not make it up to the server.
Finally, should it get to the server, there is now have a script that FIXES such orders. So, if this happens, please contact your support resource (or us) for help.
The easiest way to prevent overlaid orders is to simply SLOW DOWN (just a little bit) when in supermarket mode (i.e. scanning).