At this point I suggest you email Rev Robotics — firstname.lastname@example.org —
Tell them you are a FIRST Global Team. Describe the problem and be sure to let them know that the Kindle has not been connected to another network, you have tried to change the channel and you have done a factory reset but the problem persists. Hopefully they can provide some technical suggestions to help you resolve the problem.
Until they respond (probably not until Monday in the USA) you can continue to restart the two devices and be sure to frequently save any programs you may be developing. Sorry I can’t provide any other suggestions. I have tried to replicate the problem but I haven’t experienced any disconnects with the Control Hub and Kindle I am using. Good luck and keep use informed.