WD20EFRX-68EUZN0 in QNAP TS-219P+ with bad blocks

WD Internal Drives Desktop & Mobile Drives
2

Data LifeGuard only reports the normalised value of each attribute. Your NAS is probably reporting the raw values. The latter are more useful in this regard.

You could use a tool such as CrystalDiskInfo (Windows) or smartmontools (Linux) to give you a more detailed report.

http://crystalmark.info/software/CrystalDiskInfo/index-e.html
http://www.smartmontools.org/