I use a phantom 3 professional. Today, I went through the normal set up process and everything seemed fine. All lights were green to go. But in this case, after take off, the drone ignored my commands to go forward and instead appeared to momentarily come out of GPS mode and into ATI mode (there was no notification of this, it was just the drone behaviour), even though the drone was no more than 3 meters away. Any ideas why this may have happened are appreciated.