In this case you can try to do a factory reset of your Compute Stick. In order to do that you need to turn on the device and then press F8 several times until you get in to the recovery menu and then select the option that allows you to restore the system to factory settings, after you select that you need to wait and then you will get a screen where you need to continue with the resetting process, once it is complete the device will restart and boot to Ubuntu again.
Please let me know if the suggested workaround resolved your problem.
I think your solution did work. It is really hard to be certain as the problem doesn't appear all the time. Let me monitor for a while longer.
Thanks for your help.