Did he actually change his front wing though?
F1PitRadio tweets: "Vettel boxed for a new front wing"
Followed by "Ok, Sebastian, we couldn't change the front wing, so up 4 clicks. Cool the car, if you can"
Autosport Live reported it this way :-
82 min: In fact, Rosberg comes round in 1m40.630s, as Vettel pits for a change of front wing.
83 min: This is clearly not going as expected at Red Bull. It took an age for the mechanics to get the original front wing off the car.
84 min: Then, there was a period of running around getting a newly-arrived front wing to put on the car to be tested. Vettel is back out there now.
Since it was not shown on the telecast, there is no way to know for sure whether the change took place or not. But I believe F1PitRadio message was misleading in a way that the front wing change did take place, but maybe in the haste, the engineers overlooked to adjust the AoA on the front wing, hence the message.