This isn't going to be everyone's fix, but I thought I would post this in case it helps someone else. I've never encountered this before, but it fixed the issue immediately.
I don't normally shut down my hub. It's on a UPS and runs constantly, except for an occasional reboot for various reasons unrelated to Z-Wave. As you may or may not be aware of, the Z-Wave and Zigbee radios do not shut off when you simply reboot the hub. So when you shut down for 30 seconds, the radios will power down, and that is it when my strange issue occurred.
After shutting down for 30 seconds, I found that all my Z-Wave devices were responding, except for my Z-Wave Plus door lock. The driver was not talking to the lock at all, since status wouldn't change in the driver from lock to unlock when I clicked the button in the device details and clicking Refresh did nothing to resolve the problem. Of course my next step was a Z-Wave repair, but this didn't fix the issue. I check the lock batteries and they were at 80% charge. This lock NEVER gives me issues, so this was quite a surprise.
What finally fixed the issue was to disable the Z-Wave radio for 10 seconds, and then re-enable it. The devices did not appear in the list after re-enabling the Z-Wave radio and waiting 10 seconds, so I clicked the Refresh button and my list of Z-Wave devices appeared immediately. Went back to the lock driver page and it instantly responded to unlock and lock commands as expected.
Hope this helps someone in need.