On Saturday I had a light sleeper stay in the room that contains my DS918 so I scheduled it to power off at 11pm and back on again at 7am.

At 07:09am, I received the following alert:

Drive 4 on DS918 is damaged and in critical status. Back up your data immediately and then replace the drive.

Drive information

Brand: WDC
Model: WD60EFRX-68L0BN1
Capacity: 5.5 TB
Serial number: WD-WX11D36787UX
Firmware: 82.00A82

S.M.A.R.T. Status: Normal
Drive reset condition: Critical
Drive reconnection count: 0
Drive re-identification count: 0

A couple of minutes later I get this alert:

A UNC error has been detected on Drive 4 of DS918 . Even though the system is working properly now, we still recommend backing up your data to ensure data integrity. Please also go to Storage Manager > HDD/SSD > HDD/SSD > Health Info > S.M.A.R.T. and run the Extended Test, and then refer to the test result for the recommended actions.

However after logging into DSM, it reports that volume 1 on storage pool 1 is "healthy" and that all 4 drives are "normal". I'm running SHR1 on 4 drives with no other volumes or pools.

I've run both SMART and Extended SMART and it reports no issues.

It's now Tuesday and I've had no further warnings or alerts. Everything still reports "healthy" and/or "normal".

Do I have a faulty drive or was DSM wrong?