RE: Unexplained loss of control
OK, here's my take. The ignition is being powered from the receiver bus using a BEC to drop down the voltage of the 5 cell packs to less than 6V for the ignition. While I'm a fan of running an IBEC for just this purpose, they're designed especially for this type of setup, they provide filtering and current limitation (in case the module takes a dump) between the ignition module and the receiver bus, which the BEC does not, in fact, since most BEC are switching types, they can feed their switching noise back noise to the current source, in this case the receiver bus! I would look into either a separate ignition battery, or an IBEC like the Wike between the ignition and receiver, but you will need an actual open channel to turn the ignition on/off from the radio for these units. Of course you're getting the added benefit of an ignition kill switch when you go this route.
Pete