Jenson Button has questioned Ferrari's controversial decision to strike a tactical deal before Sunday's Russian Grand Prix.
Ferrari called on pole-sitter Leclerc to provide Vettel, who started from third, with a slipstream to help him move ahead of Mercedes' Lewis Hamilton.
But Ferrari's pre-race arrangement determined that if Vettel benefitted from Leclerc's tow to take the lead off his team-mate, then he should concede the position.
Vettel said that he would be in danger of losing third to Hamilton if he slowed down to let Leclerc through. He also argued that he made the move fair and square and without the advantage of a tow.
"I don't get why they had a deal in the first place," said Button, the 2009 world champion. "I find it very strange that Sebastian had to give the place back.
"Ferrari have overthought it. It is such a strange deal to have. If Seb gets past, he gets past, and Ferrari wins. It's just a very strange situation to be in."
Vettel ultimately retired with an engine failure, allowing Hamilton to take advantage of the ensuing virtual safety car period by taking a free pit stop and assuming the lead.
On a miserable afternoon for Ferrari, Leclerc then dropped behind Valtteri Bottas after a gamble to stop for fresh tyres backfired.
Hamilton went on to claim his ninth victory of the year to move 73 points clear of Bottas in the standings and 107 ahead of Leclerc with just 130 points to play for.
The British driver, 34, could now wrap up his sixth world championship as early as next month's Mexican Grand Prix.
"We are just trying to take things one race at a time, put one foot in front of the other and not stumble," said Hamilton.
"When you have a battle like this, you're working flat out, turning over every stone and questioning every little thing you can do better. We love that challenge and I'm really excited for the next races."