Agree with @tntpoof. Radio system seems to be the common item.
edit to clarify: (meaning it's the only thing both the Xmaxx's with different setups having the same issue have in common. Process of eliminates says it's the FLYSKY)
The TQi receiver has a built in gyro.
Those extra wires shouldn't affect anything. Why not remove those wires if you think that could be the problem while your in there anyways?
FWIW: (Traxxas TSM is in the TQi receiver itself. And those two connectors are motor temp and voltage)