[JesseK]

We had these exact symptoms during two consecutive matches at our DC district.

The core issue was that we enabled our custom comms code for the first time in a live match. We attempted a connection to a socket (RIO->D/S), yet didn't change the default timeout on the connection (2 minutes). When the robot attempted to connect during the beginning of auton and didn't connect right away, the connecting thread would block. Depending on where the code that calls the connection lives, this could (and did for us at first) block the entire robot thread. For reference, we use Java.

We never actually solved why the robot wouldn't connect to the D/S through the FMS using our custom comms on the correct ports - we simply moved in a different direction after a hitting a certain level of frustration.