What can cause “ghosting” of files on hot-swappable HDDs?

I have looked for a solution for a few days now and haven’t come up with much, so hopefully the forums can help.

My company has purchased an Akasa Lokstor M51 HDD dock and WD Red Pro SATA drives to use for a removable backup solution. The server is running Windows 2008 R2, and sees the drive in the dock just fine.

We can write to the drive with no problems, however when we swap out the drive, the files are usually shown on the new, freshly formatted drive.

So what can be causing this issue? I’m totally stumped here.