Smart-Attribute Critical Warning Bit 4 not necessary an error

[ThomasH]

Hello,
we are using a NVME "SAMSUNG MZVLB512HAJQ-00000"
The Smartmontool is reporting the following error:

=== START OF SMART DATA SECTION ===
SMART overall-health self-assessment test result: FAILED!
- NVM subsystem reliability has been degraded

SMART/Health Information (NVMe Log 0x02)
Critical Warning:                   0x04

The Attribut "Critical Warning" has different bits, signaling different status.
According to the documentation the flag for bit 4 is:
"If set to ‘1’, then the volatile memory backup device has failed. This field is only valid if the controller has a volatile memory backup solution"

The referred documentation is at ​https://nvmexpress.org/wp-content/uploads/NVM-Express-1_4-2019.06.10-Ratified.pdf (page 122).

Currently the bit 4 is reported as an error but this depends on the model (whether it has a capacitor for power loss protection).

Either this should be detected or maybe a parameter could be used to signal whether this is an error or not.