[CustomRCmodels]

I encountered the same issue , so far not with the MFU's ,
I use here my own to 2.4 Ghz modified radios , Graupner JR's and old style Futaba's
( module type , 5U and 7U mainly ), with replaceable HF modules
as well Futaba T6XA ( computer version of the older 6 channel skysport ) modified to 2.4 Ghz ... no problems here ..

but I noticed that the old Tamiya truck sound units will not work with the newer Traxxas 4 channel pistol-grip 2.4Ghz radios , the older ones do ...
and my Spektrums DX3s work , but sometimes they just keep shutting down ...

its obviously an issue with the 2.4 Ghz systems in general....
some work for these sound units , some don't ....