As an Android developer, I have a ton of spare devices running various versions of Android. One of them is the original Samsung Galaxy Note running CM10 so that I can test backward compat with 4.x.
Unfortunately, I have been unable to connect to it via adb/mtp/mass_storage for quite some time. adb via wifi works, but is dog slow when running connectedCheck.
Luckily, I figured out how to fix it yesterday (and thus the reason I am leaving this post so I can find it in a years time when I forget yet again).
It's completely incompatible with USB hubs. While all my other devices are plugged in through a single hub so that I can test on multiple devices, this CM10 device requires that I plug it in directly. Once I did that, it started working normally.
Why didn't I think of that earlier? Did I mention that none of the other devices have this problem? Just the CM10 device.