Referee Marco Di Bello apologised to FCSB officials after his decision to award Rangers a free-kick in a reprieve for Jack Butland.
The Italian official blew his whistle for a free-kick after David Miculescu pinched the ball from Butland before rolling into the net.
TNT Sports revealed after the match that the whistler blew before the goal was scored meaning an intervention could not be made.
And FCSB manager Elias Charamboulous has stated Di Bello apologised to him over the incident at half-time at Ibrox.
"The game might have been very different if the referee had made the right decision on the goal," said Charamboulou.
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"I spoke to him at half-time and he apologised. He said he should have waited before whistling, so VAR could have helped with the decision and I respect him for that.
"But it is too late now."
Ally McCoist had said of the incident: "I think he has given a free-kick and I am not sure it is.
"First thing you have got to say, far too many touches. I'll tell you what, he's got away with one there, Jack Butland.
"Two heavy touches, it's simply not a free-kick, it's as simple as that. It's a goal.
"Miculescu in my opinion doesn't do anything wrong, in fact he does just about everything right."
Asked whether Butland was expecting a free-kick for the collision, McCoist replied: "See if he is thinking that, he is the luckiest man on the planet, for me."
