Supplier real time contact developed through OTBI

We have developed a report using OTBI to extract supplier details using Supplier - Supplier Real Time.

Use case:

Each supplier have two sites (US and CA) and one contact is tagged to each site respectively.

Suppliers imported through FBDI shows correct information which shows each contact to each site. Below is working as expected

But for manually registered supplier report shows that each contact is tagged to both the sites but actually it is not. Below is the screenshot of the report

Found that this issue is happening only for manually registered supplier.

We need to understand the logic behind how supplier contacts are displayed in reports for imported suppliers versus manually registered suppliers.