[mikets]

I doubt it is noise in the CAN bus. CAN is designed for noisy environment. It is using differentiate pair so the noise on the wire can be canceled out. Are you daisy chaining the Jags? There are numerous posts talking about the RJ-11 connectors not making contact causing communication problem. When the robot is running on the ground, there is a lot of vibration that may cause RJ-11 contact issue. If you take the electronics out and run it on the table, the lack of vibration may explain why it didn't fail.