https://userapps.support.sap.com/sap/support/knowledge/en/3677045
3677045 - Field "BLOCKING_DATE" appears in table PA0003 after H4S4 migration | SAP Knowledge Base...
After migrating from ECC to SAP HCM for S/4HANA (H4S4), a new field named BLOCKING_DATE appears in table PA0003, which is the table for infotype 3.