Kvyat was the first to err, after the Toro Rosso driver attempted to pass Renault's Kevin Magnussen through the right-hander of Rascasse on lap 21.
The move went awry, causing both men to stop wheels locked together just before the wall. Both men got going again, but Magnussen would later blame the damage he sustained for a race-ending crash at Mirabeau.
Kvyat and Magnussen were summoned to the stewards and, after they studied video evidence and heard from both drivers and team representatives, they deemed the Russian - who also retired - to be responsible for the incident. He will therefore take a three-place grid drop in Canada.
The Russian was also given two penalty points on his licence, taking him up to seven - of a permitted 12 before a one-race ban - over the last 12 months.
Ericsson meanwhile was similarly blamed for an overly ambitious move on Sauber team mate Felipe Nasr at the same corner, which again put both cars in the barrier and eventually out of the race.
The Swede was issued the same penalty: a three-place grid demotion and two penalty points on his licence, taking his 12-month tally to six.