AccProduct.MaxValidDays is set subsequently for a product. Then Person.InternalName is changed for an Employee (e.g. when the Title or MiddleName is changed). Changing the InternalName leads to the execution of value templates for PersonWantsOrg.DisplayPersonInserted or DisplayPersonOrdered. Saving the PWO object fails with the error message:
"PersonWantsOrg: The following fields are mandatory and need to be filled: Valid until"
This is a product defect (33799).
This will be fixed in a future release of the product. If you require this immediately corrected, please contact Support for a hotfix referencing the defect ID 33799.