I faced the same issue with OME 2.3.X and 2.4. I had upgraded to OME 2.4 in hopes that it would resolve the issue, but unfortunately not. The affected system was a PowerEdge R515 -Windows 2012 R2 - OMSA 9.1. It turns out I had to uninstall OMSA 9.1 on the affected system and install OMSA 8.5 to get the complaint status back in OME. Apparently, OME does not play nicely with Inventory Collector 17.12.000 (included in OMSA 9.1) but likes 17.03.200 (included in OMSA 8.5).
On a side note, I have two PowerEdge R620 - Windows 2012 R2 - OMSA 9.1 that work just fine with OME. Maybe having the system updated with OS Collector 2.1 has something to do with that, I'm unsure. I also have a new PowerEdge R740xd with the same symptoms, it has Windows 2016 installed so I need OMSA 9.1 installed (with OMSA 8.5 I lose storage in the GUI). In this case it has OS Collector 3.0 installed (probably another incompatibility).
Try going with OMSA 8.5 and do another Discovery and Inventory in OME, with my R515 it returned good after a few minutes. If that doesn't work, check the support downloads for an update for the OS Collector for those chassis. Some have it, some don't from what I have learned.
Hope this helps.
EDIT: BTW, I am using SNMP for discovery on all systems, I haven't tried WS-MAN for iDRAC discovery on the R740xd yet (which I probably will have to). If your systems have iDRACs, you could try that as well.