Pirelli again face another day under the spotlight just when they believed they were in the clear with regard to their tyres.
During yesterday's second practice session for the Belgian Grand Prix both Sebastian Vettel and Fernando Alonso sustained punctures at the high-speed Spa-Francorchamps circuit.
The incidents were a far cry from the dangerous blowouts that occured over the British Grand Prix weekend at the end of June, and which led to a threatened boycott of the subsequent race in Germany.
But unsatisfied with Pirelli motorsport director Paul Hembery's explanation that what occurred was track related, the drivers approached FIA race director Charlie Whiting to seek assurances over the safety of the rubber.
As Red Bull's Mark Webber remarked: "We need answers and 'debris' is not the answer."
Alonso, who along with Vettel suffered a right-rear tyre issue, said the situation required "careful analysis".
Hembery and Whiting met late on Friday to address the matter, with the latter awaiting the former's findings following an investigation.
Hembery had earlier insisted there was no danger of a repeat of what transpired at Silverstone when five drivers sustained blowouts that put their lives at risk.
Asked directly about such a prospect, Hembery said: "It is completely different."
By his own admission, however, Hembery did suggest the situation was "a worry for the sport because we have to go out and find what it (the problem) is".
The concerns have arisen despite Pirelli changing the construction of its tyres, initially with a compromise for Germany before a permanent solution was unveiled in Hungary with last season's structure married to this year's compounds.
On this occasion, even though the track exerts extreme loads on the rubber, Hembery maintained the fault lay with the circuit and not the Italian manufacturer's tyres.
"It looks on the Red Bull as though something has been rubbing on the surface and then has just cut through it," explained Hembery.
"It rubs through and comes up to a point where it just digs in.
"On the Ferrari there are two quite clear holes through the top of the tread. There's not a lot we can do about that.
"So we have to go and look at the track and see what is between turns 13 (Fagnes) and 15 (Stavelot).
"We have seen a lot of signs on other tyres, small surface cuts, so there is clearly something. I cannot tell you what it is, but it is from external sources.
"The tyres were, apart from the cuts, very good. There is not a lot we can do, but we will try our very best to identify it and give us an indication of what is causing it."
Despite Vettel's incident, that did not stop him from topping the timesheet with a lap of one minute 49.331secs, just 0.059secs ahead of team-mate Mark Webber.
Force India's Paul Di Resta was the best of the Britons in 10th, with Lewis Hamilton 12th in his Mercedes and McLaren's Jenson Button 15th, all more than a second adrift.