Strange Disk Problems

Not sure if one or both of my disks are failing or if there’s a bug in recent firmware (as some others have recently posted similar problems, I wonder if that’s a possibility?).

My Cloud Mirror Gen 2 - Firmware: 5.21.104

Noticed an orange light on Disk 1 yesterday. No alerts on the dashboard, but Disk 1 was showing as bad, and Disk 2 as good; RAID status is healthy.

Both disks passed a Quick Test.

Started a Full Test.
Disk 1 light is still orange, Disk 2 light is now off; both disks show as bad, RAID status still healthy.
Disk 1 passed the Full Test, Disk 2 failed the Full Test and now I have an alert for a SMART failure on Disk 2.

Rebooted the NAS (have tried warm and cold boot).
Disk 1 light is now blue, Disk 2 light remains off.
Disk 1 is now showing as good, but Disk 2 remains bad. RAID status remains healthy.

Any thoughts or recommendations on how to proceed? Should I replace one disk, both disks, or the NAS? Or wait to see if a firmware update addresses the problem?

I already have a full backup so I am not concerned about losing data, I’m just wondering what to do about the hardware.

Update in case anyone has a similar problem:

I decided to trust the diagnostics and bought a replacement disk (WD Red Plus 2TB). The RAID rebuilt successfully, and both disks are now showing good, the RAID status is healthy, and the blue light is on for disk 2.