Hi,
the first screen shot with the 'wrong fields' is actually SAP standard. The second one must be a custom development/configuration.
Please check if there is perhaps an implementation of the WDDOMODIFY badi active/not active anymore. If there is, check the coding for the reason why SAP standard is displayed instead of the custom screen.
It could also be a change in the component configuration of the PO fpm - again check for custom changes here.
Regards,
Robin