So... Yes, he did overtake, but when the safety car ended he was behind so it's fine(??).
Ok then, one driver either side of the leader behind the safety car, just nudge forwards and backwards a bit from time to time. As long as he's ahead at the safety car line it's all good. (!?)
These small overtakes happen constantly during safety car periods and on the formation lap as cars accelerate/brake sharply. They have never been punished previously as long as an advantage is not gained or the place is not given back. If this was punished, then next season it would open the door to lead drivers brake testing the person behind to give them a 5s penalty when they go an inch in front so would become unworkable.