Topology Scan not working properly

Using common topology scan tools the topology is not detected properly with PNS V4 devices. The problem can be reproduced as follows:

1. Use TIA Portal to setup a simple configuration Test PC – PNS V4 – CPU15xx. Download configuration and perform a topology comparison. Port 2 of PNS V4 Device will not show valid connections
2. Now use Siemens Proneta V2.0.9.3 for the same setup to scan the topology. A wrong topology is detected.
3. Setup Topology PC – PNS V3 – PNS V4 – CPU15xx and perform scan with Proneta V2.2.0.12. The topology is also invalid.