Sebastian Vettel was left wondering if he had "missed something" as Ferrari's tactics were again scrutinized in Russia, where the German was asked to let Charles Leclerc through.
Vettel, who won last time out in Singapore, appeared to benefit from Leclerc's slipstream to emerge ahead of the pole-sitter at the first corner.
But Ferrari quickly sought to push Leclerc past Vettel again, with the younger driver having fumed in the last race when pitting strategy handed his team-mate victory.
It ultimately counted for little as Vettel retired shortly after Leclerc nudged in front, allowing Lewis Hamilton to pit under the virtual safety car and claim victory.
Vettel was still left confused by the fuss around Ferrari's tactics, though, telling Sky Sports: "I don't know exactly what happened there.
"I think we had an agreement - I spoke to Charles, in particular, before the race. I thought it was quite clear. Maybe I missed something. I'm sure we will talk about it.
"It's bitter today because we wanted to have the cars finishing one and two, and now Charles is third. It's not the result we wanted."
Asked for details of his agreement with Leclerc, Vettel replied: "I don't want to share, to be honest. It was not a great deal, but I don't want to put the team in a bad position afterwards because somebody said something here, there.
"I know it's not fair because people deserve to know, but it's no big deal. Obviously, I was in third, Charles was in first, and we were talking about a strategy to find a way past Lewis.
"I had a very good start so there were a couple of options on the table. Sorry, I'd prefer not to [say] anyway."
Vettel was still confident he and Leclerc had been able to enjoy a fair race until the point where he was pitted and his teammate nipped in front.
"We did [race] until the pit stop, because I lost the lead during the stop and then the car broke down, so it's a bit irrelevant," he said. "Up to that point, that's what we did."
Despite the frustrating end to the weekend, Vettel also saw positives in the pace of the SF90, having endured a miserable winless season prior to his Singapore success.
"From my point of view, it was a matter of time before things started to click - whether that was a win or a good position in a race," he said. "The positive thing overall is that the car is good. I think today is the first race where we had more pace than Mercedes.
"It wasn't really the case in Singapore - although yes we won - and also the race before, in terms of raw, race pace, Mercedes still had an edge. So that should give them a bit of a headache. It's good for us."