For quite some time I have observed a LOM warning in VMware health status tab on an HPE Proliant ML350 Gen10 server. It seems like it reports the warning on two NIC that are down, even though there are unused by ESXi.
[Device] I/O Module 3 LOM_Link_P3
[Device] I/O Module 4 LOM_Link_P4
The new ILO5 version 1.37 seems to have fixed the issue – if the warning persists after updating, then try to clear the IML log on the ILO.