The job "[T2] Post-Upgrade-Marker Tests - Network" on CNV 4.20 breaks when ran in a PSI cluster, because IPv6 support is required for some of the test cases. Example of a failed job:
https://jenkins-csb-cnvqe-main.dno.corp.redhat.com/job/test-pytest-cnv-4.20-post-upgrade-marker-network/26/

This doesn't happen on older CNV versions, such as 4.14, because tests behave differently there and gracefully skip test cases if required feature(IPv6) is not supported.

We need to figure out which versions are affected by this problem and update job configurations to prevent broken builds.