R830 | Slot Empty Issue

I've got a weird one for you.

I have a PowerEdge R830 with a PERC H730 controller. 16 drives, two virtual disks. All firmware fully up-to-date.

My issue is with the second virtual disk, or perhaps more accurately two specific slots in the server.

Everywhere I look, the server tells me that Slot 2 is empty, except in the logs where it correctly states that a disk was inserted into Slot 2.

I also have a similar issue with Slot 15. When a disk is inserted into Slot 15, the disk goes through a rebuild procedure. After perhaps a day or two, the disk is then listed as 'Removed'. 

The issue is not related to the disks themselves. Replacing the disk doesn't change the outcome. The same disks work when used in other slots. 

My first thought was to replace the backplane, but that didn't solve it. So I replaced the controller and imported the foreign configuration of the two virtual disks. Even the new controller couldn't 'see' the disk (despite the disk being shown correctly in the logs).

I've also seen throughout the last few weeks a few cases of disks randomly disconnecting or failing, and immediately being rebuilt by the server.

Everything tells me that this is a backplane issue, but it just can't be affecting both in exactly the same way.

From what I can see, there's two next logical steps for me to take but I would like to see if other people have had any experience with this kind of issue.

Do you think it's the SAS expansion board is faulty? Is it worth the expense of replacing it? Or is it perhaps possible that the issue lies with the disk configuration, and that deleting and rebuilding the virtual disk from scratch is the way forward?

Thanks in advance!