The two most important components for the Power Shield are out of stock (MOSFETs and current sensors), so even if you upload the BOM and PnP you are still not able to order due to the world-wide chip/silicon shortage.
JLC changed the BOM and PnP format, so not quite sure why it didn’t take it. I guess you are the first to order recently because you just didn’t know the components are not available.
Even if you fix the file formats, you need to wait for the components to come to the factory, which currently is sometime end of next year.