I didn't have autofs installed, so I tried following the steps in that article. No joy. But since I didn't have autofs before the last kernel update and it was working, it seems I've got some other problem.
As for /var/log/debug it's showing:
Apr 10 14:40:52 drook-desktop kernel: [1518832.644828] usb-storage: device found at 19
Apr 10 14:40:52 drook-desktop kernel: [1518832.644832] usb-storage: waiting for device to settle before scanning
Apr 10 14:40:57 drook-desktop kernel: [1518837.645929] usb-storage: device scan complete
Apr 10 14:40:57 drook-desktop kernel: [1518837.666881] sd 10:0:0:0: [sdb] Mode Sense: 04 00 00 00
To me that looks like everything is detected properly. And a manual mount works just fine. Guess I'll wait to see if a future kernel update fixes it.