LSI MegaRAID reports bad drive but SMART status is good

I am setting up a NAS with 8 known-good 8TB WD Red drives from a previous NAS. When I configure RAID 6 across these drives my (untested) LSI MegaRAID 9265-8I starts beeping and reports that that drive is bad. However, when I run WD's LifeGuard Diagnostics it reports that all of the SMART tests pass.

MegaRaid failure event as reported by MegaCli:

Code: 0x00000191
Class: 2
Locale: 0x02
Event Description: Diagnostics failed for PD 18(e0xfc/s7)
Event Data:
===========
Device ID: 24
Enclosure Index: 252
Slot Number: 7

Things I have tried so far:

• Erasing the "Bad" drive completely
• Setting the "Bad" status to "Good" and reconfiguring the array
• Swapping the SFF and sata cables (the same drive failed in any position)

Anyone know what else I should try or if I am likely looking at a bad drive or a bad RAID controller?

The issue ended up being a bad RAID controller. I briefly came to the conclusion that it was a cable issue due to swapping the cables and having the "bad" drive change slots but eventually realized that the controller was remembering the "bad" drive. Further swaps of the cables and re-configuration showed that it was always slot 7 that failed no matter what drive or cable was used.

After installing a known good MegaRAID controller I had to hand, I was able to successfully configure a RAID 6 array with all 8 drives. The bad raid controller will be returned and replaced.