Ours is jumpy when I hit "test" or whatever that button is marked as on yours. It doesn't need much space to perform a braking cycle then release without leaving any pressure on the pedal. I wonder if it pulls back (toward the front of the car) to help make sure the pedal doesn't have any pressure left on it.
Now, if you push the button and it "stutters" (partial apply and release rapidly repeated), that's a problem.
Brake Buddy tech support is very helpful, just call them.
Every once in awhile, somebody says they burned brakes because their BB didn't fully release. I'm not taking sides, I don't know what caused it, and I still use Brake Buddy. But I DID tap into the brake light wiring and connect an LED stop light (amber, illegal to show a red light forward) that I bungee to the front of the toad's rearview mirror. I can see it light when BB applies braking, AND see it go out when BB fully releases the pedal.