I had the exact same problem. I figure running on the mini bike with the mod for enhanced speed caused the drone to get lost while I was racing down the road. Suddenly my FPS dropped to nothing hardly. Everything was a blur. So recommend if the player is racing down the road with the drone out the drone hibernation mode till the player stops moving. Then the drone can "catch up after a period of time" and avoid the NaN NaN issues. If necessary set the drone location to the players location once the player stops moving.