The alleged incident could land the Celtic striker in more trouble with the ruling body and his club.
The 23-year-old former Hibernian player has already been fined by the Parkhead club and faces SFA disciplinary charges after he was filmed singing about administration-hit Hearts' financial problems in a bar before the Edinburgh derby at Tynecastle last Sunday.
Celtic manager Neil Lennon warned Griffiths, who joined the SPFL Premiership champions from Wolverhampton Wanderers in January, that the transgression was "his one strike".
Lennon added: "I don't want him doing any more - otherwise his career at Celtic won't be as long as he maybe wants it to be."
Griffiths was charged with a breach of disciplinary rule 86, which covers "not acting in the best interests of Association football".
Fresh footage from the same bar shows Griffiths standing
up and dancing about among Hibs fans as they sing the song about Skacel.
Lunny could issue a second charge to the Scotland striker, but more probably the charge will be reissued to include the new footage which would make the matter more serious.
In 2005, former Hibernian forward Derek Riordan was fined by the Easter Road club and forced to apologise to Skacel when he was filmed singing the same song in a pub with other fans but that incident predated judicial panel protocol.
Celtic were unavailable