It is a "recurring" yet not so well known issue.
This unit test fails if any part of the DPDK did not release all
(hugepage backed) memory and associated hugepages before exiting.

In your case here, there is a virtio-net device that the container
tries to get its hands on because DPDK scans and probes all available
resources by default (and fails to, in this case, but that's not
important).
Triggering this virtio-net probing makes ethdev allocate its shared
memzone for port data, but nothing in ethdev releases the memzone when
exiting.
Fixing this could be tricky... as the current ethdev code is really
vague around which locks protect what (if anything..).

I think we hit this issue in the past, and avoided it by running the
tests with dynamically linked DPDK binaries (and by doing this, avoid
the net drivers get loaded).

I can see that you are running the unit tests with a static binary in
the report you sent.
I think the default is shared mode, so I wonder what could be the
reason why UNH builds with static here.
In any case, could you have a try and switch to
-Ddefault_library=shared (or remove forcing to static mode)?