Our team has had a similar problem it could be due to
1) The chains being to tight on your drive train
2) The motors trying to do too much work on the robot and the jaguars are resetting themselves
3) Your gear ratio on your drive train is geared to low and you need more torque
4) Your robot might be too heavy
Solutions:
1) Loosen chains on your robots (unless your not using chains)
2) Use a larger guage wire on you robot and jaguars
3) Change the gear ratio going from small to large
4) Loose weight (I suggest weight watcher
)