BetterCharacterControl setDucked(true) makes player jump

Hello, I trigger setDucked() of the BetterCharacterControl with the following code:

public void onAction(String binding, boolean value, float tpf) {
    if (binding.equals("StrafeLeft")) {
        leftStrafe = value;
    } else if (binding.equals("StrafeRight")) {
        rightStrafe = value;
    } else if (binding.equals("MoveForward")) {
        forward = value;
    } else if (binding.equals("MoveBackward")) {
        backward = value;
    } else if (binding.equals("Jump")) {
    } else if (binding.equals("Duck")) {

Now, I’ve checked via System.out.println(); the value of value in the “Jump” and “Ducked” condition. Everything seems to be OK. For some reason, my player does not duck, but jumps. It jumps even higher when ducks than when I press the jump key, ie. when he jumps via jump();

What am I doing wrong? Thank you!