I haven’t got a circuit diagram for the Servo Crumb, but it seems strange that the IC should get hot. I’m assuming the overheating IC is the one marked MEGA328P? The Servo Crumb looks to have a reverse polarity diode, so it’s probably not an incorrect connection. Was the Servo actually working when it got hot? In theory AtMEGA328 shouldn’t get warm, regardless of how much work the servo is doing. It might be worth contacting 4tronix directly – in case it is just a faulty Crumb. I’ll drop them an email too.
All the best,