Thanks for your response, mharvey. I also thought Solarwinds would exhibit the same behavior, but upon rediscovering the drives, the old "unresponsive" drives show alongside the new "good" drives. Even if I unmanage drives and re-manage drives, they still persist to show up.
As you can see, the nearly full drives are the ones that have been dropped, and the new one is displayed below.
Any thoughts?