Mapping error in PI 7.4 dual stack

Dear Experts,

    Recently we upgraded our system from PI 7.1 to PI 7.4 dual stack.

Scenerio is ECC->PI->SOAP(Webservice) synchronous

Issue in detail:

     We are creating a invoice in ECC system through PI its updating in third party site using SOAP webservice and will get a reference number from that site and then updating in ECC as in synchronous way.

Invoice data's are reached PI sucessfully from ECC but it not updating in the site and getting below mapping error after upgarded to PI 7.4.

   Kindly help to sort out this issue.

Best Regards,

Monikandan