I believe it is a programing or setup issue, I say this because in 2006 I built a 40% Carden 260, and flew it over 500 flights with a Spectrum DX-7 with two batteries plugged into a single Fromco switch that powered the ignition and receivers on the same circuit without a single hickup. I did this as a test bed after speaking with the boys at Desert Aircraft about their ignition modules and Fromco that set me up with a switch the had a two battery input and a 3 power supply output. Anyway I am happy to say the 260 is still alive and well today.
Bob