It was a simple unforced error.. Nico didn't have his head in the game. I cannot believe he did it twice. We've seen just about every other driver on the grid do the same kind of thing though, except Alonso.. I still think he's part machine.
The shit of it is, if Lewis had followed his engineer's suggestion of maintaining a gap, Nico might have gotten away with the second mistake.
That call didn't make any sense to me anyway.. why the hell would you want to maintain a gap then fight at the end of the race on old tires. Make the pass when things are fresh, then dictate the pace at the end... especially considering Nico's lack of overtaking ability.