Turnbull had only just come on as a replacement when he followed up a kick-off which resulted in Edinburgh centre Nick De Luca being upended.
He received a yellow card from the referee and returned to the fray 10 minutes later from the sin bin but by then the tide had turned and the Scots managed to cling on for a gritty 16-17 victory at Parc y Scarlets.
A hearing of the WRU Professional Disciplinary Panel will take place at the Millennium Stadium this evening.
