Origin of Contact

Hello experts,

we have a problem with mergin contact data from different sources. As unique identifier we have choosen the SAP customer number. In the screenshot you can see the settings.

The contact was first transferred from the shop to the marketing cloud via the Origin SAP_Hybris_Consumer.

With the implementation of another marketing area, we also created another Origin of Contact.

When syncing with the shop, however, the contact data is not merged but a new contact is created.

As soon as the Origin of Contact is another, the contact is no longer merged via the SAP customer number.

Does anyone know why this is happening and how to fix it?

Thank you very much!
Christiane