If you have two processors showing the same error it doesn't sound like the customer needs to spend on HW - it sounds like a configuration error.
Nothing I described is service affecting because you are only reading/checking config.
As well as Atlan working, Corosync then must also be working, for the duplex. Quick ping test from atlan would confirm but if it wasn't you would have heard about it by now, especially if the processors switched over OK.
Is there any IPDA? IPDA is configured to use same eth ports as the admin lan, or different? Is anything bonded/VLANs?
I would regenerate the firstinst file like I described above, and confirm it is correct.
If you do need to reconfigure the lan, the correct way is to reconfig the XML, and then use recover_4K to push the changes in, but that will stop the openais service (no telephony). The portal reconfig works for some things, but it would still cause an outage.