https://userapps.support.sap.com/sap/support/knowledge/en/2732548
2732548 - Cannot draw a traceability link from/to a sub-process in a BPM - SAP PD | SAP Knowledge...
It is not possible to draw a traceability link between a sub-process and a diagram in a Business Process Model (BPM). The Impact and Lineage Analysis window...