Liverpool head coach Andoni Iraola has questioned the professionalism of the fourth official in his side’s 2-2 draw with Nottingham Forest on Saturday because of the length of time it took to input the correct shirt numbers into the substitutions board.Iraola had been attempting to introduce three players shortly before a controversial penalty was awarded on 70 minutes when goalkeeper Alisson brought down Forest’s Neco Williams inside the box after a quick throw-in.He was angry at the time it had taken to process the planned changes as fourth official Tim Robinson was unable to flash up the substitutes’ numbers due to a malfunctioning electronic board.“I cannot explain because I don’t have an explanation,” Iraola said after the game, before telling its UK broadcaster TNT Sports: “A professional fourth official cannot take three minutes. We’d already given him the subs two or three minutes before. I was already angry because in the previous stoppage we couldn’t make the subs and then before the throw-in I thought we could do it.”At full time, Alisson kicked one of the boards in anger. The club’s vice-captain was raging following the penalty decision, which upset Liverpool’s players and Iraola as it came during a time when they were trying to make changes.