I have 25 ESXi servers that have the 7.3 vib on them, but OME is reporting that 7.2 is installed. We are running ESXi version 5.1.0, in the past it has always updated just fine. We also have some at our DR datacenter that are running the same version and report correctly inside of OME. I have them in two groups one for the MGMT IP and another for the iDRAC IP, and I've noticed that my iDRAC IP's are all in the unknown group.
I've tried re inventoried the hosts and tried refreshing the status, I've rebooted the host as well. I have verified that the 7.3 vib is infact installed on the hosts as well.