Joe Marler could face another suspension after appearing to kick hooker Arnaud Heguy in the head as Harlequins saw off Grenoble 30-6 to reach the European Challenge Cup final.
The England prop was in his first game back after the two-match ban for his "Gypsy boy" slur against Wales tighthead Samson Lee during the Six Nations.
The 25-year-old's kick to Heguy in the 26th minute of Quins' semi-final was not picked up by referee John Lacey, but Marler could still face a citing and a disciplinary hearing.
Any ban could now jeopardise Marler's availability for Harlequins' Challenge Cup final on May 13, and even England's three-Test tour to Australia in June.
Marler initially escaped censure for his taunts against Lee in England's 25-21 Six Nations victory over Wales at Twickenham on March 12.
Global governing body World Rugby later intervened and called a misconduct hearing however, dissatisfied with the leniency of Six Nations and RFU bosses.
Marler admitted the charge and was banned for two matches and fined £20,000.
The loosehead prop had only just returned from that suspension for Quins' last-four European tussle at The Stoop on Friday night, and has appeared to waste little time in courting further controversy.
Jamie Roberts, the fit-again fly-half Nick Evans and George Lowe claimed the tries that sent Quins into their first European final since winning the Challenge Cup in 2011.
Conor O'Shea's men will now face the winners of Saturday's other semi-final clash, between Montpellier and Newport Dragons.
Harlequins' 13-6 half-time lead was not nearly sufficient, by virtue of both their early dominance and Grenoble's threats of a recovery.
No one of a French persuasion much fancied stopping juggernaut centre Roberts in fifth gear, and the Wales midfielder duly trucked over for the first-half's sole try.
Ben Botica's conversion and two penalties had Harlequins in control, but Jonathan Wisniewski was able to land two goals of his own to cut the home advantage.
Quins were 13-3 to the good just inside the first quarter though, and singularly failed to seize on that rapid start for the remainder.
Perhaps the ease of their early dominance lulled O'Shea's men into a false sense of security.
Whatever the reasons, Grenoble created enough of a scrap to scrabble a foothold.
Three times though the visitors set themselves a fine platform, only to botch their approach play at the critical stage.
Quins somehow escaped without shooting themselves in the foot however, and were able to close out the clash after the break despite yet more fluctuating fortunes.
Fit-again fly-half Evans capped his return from a broken leg with the try that effectively sealed Quins' victory, the Kiwi playmaker reclaiming his own grubber to score just ahead of the hour.
Danny Care sent a grubber of his own through next, allowing centre Lowe to dot down Quins' third and final try.