A Red Bull representative has been summoned to a stewards' hearing at 7.15pm local time [6.15pm] to answer charges that both drivers 'failed to stay to the right of the yellow line at pit exit'.
With regard to Verstappen, the Dutchman took his intermediate tyres a lap longer than Carlos Sainz and Charles Leclerc - who had already lost the lead through a Scuderia strategy blunder - overcutting the Monégasque as he struggled on his out lap with cool hard tyres.
But emerging from the pits, Verstappen fought a snap of oversteer on the extreme inside of Sainte Devote, with his left-front and rear tyres coming daringly close to crossing the yellow pit-exit line on first look.
Announcing the protest during his post-race media call, Red Bull team principal Christian Horner revealed Ferrari had made a protest against Verstappen only.
Asked for his thoughts on the incident, he said at the time: "All the footage we've seen we've been content with so we'll see."
But it has now transpired Ferrari has also protested Perez for the same offence.
Potential five-second penalty would drop Perez and Verstappen down to third and fourth, handing Sainz and Leclerc a one-two finish.