Expect it’s a stress manangement tactic.
Other than his stage wins, he appeared pretty chill with the jersey until the 20th day of the Tour that he won.
Wiggins has always said he's like this and it's what makes him a good GT rider, very little flusters him and he never really gets too emotional and goes absolutely all in.
What's up with G? Seen him in several jersey ceremonies now and it seems like he is really struggling to show some positive emotions.