I have been suffering from the same problem, and it is solved now.
As someone have mentioned in another thread, drive write cache is being disabled by some RAID devices, notably Adaptec. After that, it cannot be reenabled just by ATA command, which is what hdparm -W does. To reenable write cache, you need to use SCT command:
smartctl -s wcache-sct,ata,p /dev/sdg
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.15.0-48-generic] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF ENABLE/DISABLE COMMANDS SECTION ===
Write cache SCT Feature Control is set to: Controlled by ATA (persistent)
hdparm -W /dev/sdg
/dev/sdg:
write-caching = 0 (off)
hdparm -W1 /dev/sdg
/dev/sdg:
setting drive write-caching to 1 (on)
write-caching = 1 (on)
