The Chase drive will act up; jittering, stuttering, jerking, etc., if it cannot keep up with your demands (possibly refusing to work at all if left uncorrected). It will continue to jerk and jitter even with the line off. When this happens you will need to "power cycle" the drive before it will work properly.
This simply means that the drive needs to be unplugged for at least 30 seconds before you try to run again. You may also need to press and hold the paring button on device until the blue light on the bottom of the device comes on and begins to blink.
But you also must fix the cause - which means making adjustments to the course. If after making adjustments, it begins to jerk and jitter again you need to repeat the adjustments and power cycle again - until you can get the drive to successfully run without being overtaxed.
See: Chase motor acting up? for tips on adjusting the course.