Poweredge R730 multipathing

I have a Dell R730 8-bay LFF server that I was planning on using in some capacity for TrueNAS, but I've ran into a problem that I can't figure out for sure. Everything seems happy on the server in the iDRAC, no errors of any kind, but in TrueNAS, the SAS disks show up as Multipath disks, but the multipath status is degraded. I've tried different SAS disks, a different PERC H330, different cables, all to the same result. The only thing I haven't tried is the backplane. But does the H330 and backplane even support multipathing? It sure doesn't look like there's an expander on the backplane, and it appears like the 'A' and 'B' cables are direct connections for the drives to the HBA (Each cable handles the data path for four drives). Typically, if there was some sort of path issue with the cabling, even if it was A was connected to B and vice versa, the sever would know it and complain. But it's not complaining about anything.

To add to that, I tried on an 8 bay SFF R730 also with a H330, and with a SAS disk inserted, on that server, TrueNAS does not detect it as multipath capable. That backplane appears to be functionally identical (form factor of the drives aside) to the 8 bay LFF backplane.

So does anyone know if this backplane actually supports Multipath, or if it actually only supports a single SAS path per disk and TrueNAS is doing something goofy?