Mercedes may be hiding engine reliability concerns with their power units, suspects RacingNews365.com F1 journalist Dieter Rencken.
This follows a weekend in which Valtteri Bottas was forced to use a new power unit for a second consecutive race, having taken a fresh engine and grid penalty at Monza. After just one race, he moved onto another new one in Russia, with the previous unit being sent back to Mercedes' engine headquarters at Brixworth for analysis, as the team confirmed they had discovered an issue.
With Williams also forced to change a Mercedes engine for Nicholas Latifi, Rencken reckons there may be something bubbling under the surface.
"We keep hearing that they changed this engine because of an endplate that was cracked, and they changed Nicholas Latifi's engine because they discovered something," Rencken told Thomas Maher on the RacingNews365 Formula 1 podcast.
"I'm wondering whether or not Mercedes really does have some form of reliability challenge. I wouldn't call it a problem yet, but I'd certainly say a challenge. That there are some issues bubbling under and that basically I think that could change the face of the season.
"Honda seem to have got their reliability issues together. Max wouldn't have taken his engine in Russia, had he not basically written off the one in Silverstone in that crash. He wouldn't have had to take it [in Russia]. He may have taken it, but not necessarily so. That crash made sure that he had to take it at some stage."
However, Rencken also acknowledged the possibility that Mercedes may not have had a power unit problem at all and simply wanted to put Bottas further back in the pack in a bid to baulk Max Verstappen's recovery from the rear of the grid. If that was the intention, it backfired badly as Verstappen overtook Bottas with ease into Turn 11 early in the race.
"We were rather surprised when we discovered that they had done another power unit change for Valtteri," Rencken said. "There are two possible scenarios here. One is that there was a genuine mechanical issue and if there is then, of course, they've got a reliability problem.
"They say that there was some damage that they picked up, well, possibly so, but the damage wasn't particularly hard. So it didn't quite ring true. But whatever. Let's give them the benefit of the doubt.
"It just doesn't stack up, it could be nefarious. Incidentally, I have no problem with that if they want to play those tactics. That's their prerogative, let them play it, I'm certainly not going to criticise them about it if that is the case. But if it's not the case, then I really do fear for Mercedes from a reliability and an engine perspective going forward, particularly for Lewis [Hamilton's] car."
Asked about whether the possibility of a less than perfectly reliable engine is the more likely one, and whether there may be some hidden panic at Mercedes with seven races remaining if Hamilton does require another new engine, Rencken pointed to reliability issues being the more likely scenario.
"Ultimately, I'm starting to wonder about the various disruptions at Mercedes," he said.
"For example, Andy Cowell, who of course, was the CEO of the engine company which is separate from the team, left about 18 months ago, James Allison has moved out from day-to-day control and management of the technical function...
"I'm starting to wonder about how they've lost a lot of people to Red Bull Powertrains, I'm starting to wonder where there isn't just this slight shift in balance [to Red Bull]."
Lewis Hamilton claimed his 100th Grand Prix win to move into the championship lead, but it's Red Bull and Max Verstappen who will be happiest after the Russian Grand Prix.