Strange SuperMicro JBOD issue

I'm having a strange issue where my front-end server can only see the drives connected to the front expander, and not the rear expander. The strange thing is that if I remove one of the SAS cables going from the front expander to the "backplane" (I think this is the right word), all the drives then show up.

Here is a picture: Any ideas?

What drives are in your JBOD?

and what is the model HBA/Raid card?

Western Digital WD2000F9YZ. I should mention that everything worked fine until a few days ago. I had all the cables plugged in and could see all the drives.

I have 2 HBA's and have tried both, tried different PCI-E ports, and a different OS. LSI 9207-8E SGL.

Where are the 3/4 SAS cables connected to? the HBA ports or something else?

Can you do a more detailed diagram?

What OS? Can you do a SAS Topology dump?

The JBOD has a card in the back that provides you with 4x SFF-8088 ports. From that card there are 4 SFF-8087 cables. In my configuration, I have 2 plugged into the rear expander, and 2 plugged into the front expander. If I leave 2 in the rear, and 1 in the front, it works. But if I plug 2 in the rear, and 2 in the front, only the front 24 drives show up in "diskmgmt" in Windows, or "format" in Solaris.

How can I do a SAS topology dump?