'Failed to find cgroup2 mount' warning when running 'ss -le' command in certain network namespace setups

SUSE Linux Enterprise Server 15

When checking detailed listening socket statistics with the 'ss -le' command inside network namespaces the following warning might prepend the expected output (more than once) :
  Failed to find cgroup2 mount

Example dialog :
15sp6:~ # ip netns exec ns1 ss -le
Failed to find cgroup2 mount
Failed to find cgroup2 mount
Netid   State    Recv-Q   Send-Q   Local Address:Port      Peer Address:Port   Process                                  
nl      UNCONN   0        0              0.0.0.0:4444           0.0.0.0:*      users:(("netcat",pid=3091,fd=3)) 
ino:22823 sk:1 cgroup:unreachable:787 <->rtnl:kernel                *       sk=0 cb=0 groups=0x00000000
...

The warning can be ignored.

The 'ip netns' command is exclusively for network namespace management, thus it "lacks" support for some cgroup functionality - among other the above condition.

The 'ip netns' command is implemented with use of not only network namespace management, thus the environment it prepares "lacks" support for some functionality - among other the above cgroup condition. ('ip netns' utilizes mount namespacing too)

A similar warning (Failed to open cgroup2 by ID) can also be observed without network namespaces, but that is a different issue for which a fix has been developed.
That particular issue is caused by the fact that a socket may survive its creation cgroup or the originating cgroup is not visible to the ss user (cgroup namespace), so the cgroup ID cannot be resolved to a path.  
As an example if the nfs-mountd.service is restarted the sockets may survive, but the hierarchy belonging to the service in /sys/fs/cgroup/unified/ will be replaced. This means there is no malfunction as such, but the link between the socket belonging to a service that has been restarted and the cgroup hierarchy of the service is not resolvable by the ss (diagnostics) tool.
A maintenance update containing the fix for the second (non namespace related) issue targeting SLES 15 SP5 LTSS and newer has been submitted and this document will be updated with information about release information when it has happened.