I have a strange situation.
In a specific scenario, for sales and return documents we use some custom partner function at item level.
This partner function is added manually at the sales order item level and after that copied to invoice and return order.
The problem is that for a specific item category (ZTAB) the custom partner function is not copied in the return order.
If I compare the copy control of the ZTAB item category with let say ZTAN item category, for which the partner function is copied, they look the same. Still for one of them the ZC partner function is copied and for the other it isn't.
Does someone have a solution for this?