This phenomenon has to do with the design mechanism of the Mac itself.
The interface of Apple's original SSD is classified as either AHCI PCIe or NVMe PCIe.
For earlier Mac models, the original SSD only supported the AHCI PCIe interface whereas for later Mac models, both AHCI PCIe and NVMe PCIe interfaces are supported.
Therefore, if you use Apples's original NVMe PCIe SSD or NVMe's JDM products on earlier Mac models, a "VDH002" message will appear when you hold down the D key to conduct detection during startup.
Yet, this does not affect the normal use of your product. The issue is merely a result of Mac's design mechanism itself. If you wish to check the health status of your JDM products, you may download our JetDrive Toolbox for further examination from the website provided in the link below.