Hello,
You can check CL_CRM_MW_MDM_DATAEX_PRODMAT->FILTER_PRODUCT_MAT.
This class is responsible for executing the filtering logic based on the filters configured in the T-code:CRMD_MDM_FILTER. This will help to identify why the filters didn't behave as expected.
Filter table: CRMC_MDM_CRITVAL.
Regards,
Sonal