Vendor in condition & in item & different to vendor in purchase order.

What causes this issue?

The split invoicing condition vendor is not the same as the purchase
order vendor. This is not possible when you use ERS (ERS flag is set for
this position).

System Response

Error message.

How to fix this error?

Insert the purchase order vendor for this condition or remove the ERS
flag for this purchase order item or remove the
split invoicing flag of the condition.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.