Orin S-parameter files unsymmetric (unidirectional connections)

The Jetson Orin NX Series and Jetson Orin Nano Series Signal Integrity Simulation Application Note (Ver 1.5, Release date 2023/01/27)
contains several S-parameter files.

We looked into the files for PCIe,
with the Hyperlynx Touchstone Viewer.

According to the frequency responses, in the first file there is transmission on 8 paths:
but not in the opposite direction

So it looks like there is only a unidirectional connection on these paths.
Similarly, in the second file above we see unidirectional connections on 32 paths.
Is this the expected result?

Other files
do not show this phenomenon. In them there are 8 resp. 12 bidirectional connections.

Best regards

UPHY’s on-die termination model is unidirectional and the valid path is only from on-die to BGA for TX, and from BGA to on-die for RX.