moveForward crashes server about compactnpclib HOT 3 CLOSED

public class AISneakLookout extends AICustom{

    private boolean lookDir;

    public AISneakLookout (NPCPlayer player) {
        super(player);
        this.getPlayer().setSneaking(true);
        this.setYaw(180);
    }

    @Override
    public void tick(){
        super.tick();
        this.getNpc().moveForward(0.5F, 0.1F);
        if(!this.hasTimePassed(2000)){
            return;
        }
        this.lookDir = !this.lookDir;
        if(this.lookDir){
            this.setYaw(135);
        }else{
            this.setYaw(-135);
        }
    }
}