McLaren has inked a deal with Mercedes for a supply of customer engines from 2021.
The unconfirmed news is being reported from Sochi by authoritative sources like Germany's Auto Motor und Sport.
But other sources report that meetings involving Zak Brown, Andreas Seidl and Mercedes' communications team definitely took place in the McLaren hospitality on Friday.
Other meetings between Brown and Renault's Cyril Abiteboul also occurred.
"There are no confirmations or denials, just smiles," AS newspaper's correspondent at Sochi, Jesus Balseiro, reported after checking with McLaren.
McLaren was powered by Mercedes between 1995 and 2014, winning the title with Mika Hakkinen and Lewis Hamilton.
Team driver Carlos Sainz says McLaren's 2019 season has been a "perfect" step forward for the team, but another major step is needed for the future.
"When you have a one second gap to those ahead of you, you need conceptual changes," he said at Sochi.
"I don't think you will see a radical change because we have a solid basis for next year's car, but it is necessary to take some risks to eliminate that second gap.
"If you don't try, you won't find it," Sainz added.
