Once Ejected Drive Will Not Spin Down

Until the latest update to macOS Mojave my WD Elements USB3 4Tb HDD would spin down once ejected and I then switched off the power. Now when I eject, the drive keeps spinning. If I wait several minutes the drive’s internal awareness of access spins it down and I can switch it off. I have done nothing to the drive in the interim, installed no other utility or app that could have any impact. Thus I assume that a change to macOS Mojave has changed the behaviour or my WD HDD. Does anyone else have this problem? Do I need some new driver? Will I harm the HDD by switching it off whilst it still has the disk spinning whirring sound? Once ejected the light is off on the drive enclosure. Switching it off does not result in a macOS error message and the drive remounts ok. My concern is whether these HDDs park the heads when the spinning sound ceases. Therefore, is just cutting the power harmful? Thanks in advance for advice.

This could be your solution like it was for this person.

Alas, my drive remains in the same USB outlet that it has been for over a year. It is connected to my 5K 27inch iMac all-in-one computer. Thanks for the response however.

Same problem here with macOS 10.14.4, and the drives now take perhaps an hour to be usable on next connection. It’s an Apple issue, though, not a WD one.