Stewards had to step in to prevent a confrontation between Dons boss Robinson and a group of Bees supporters following the home side's 3-2 win.
Brentford chief executive Mark Devlin confirmed there had been an incident as Robinson was walking to the team bus, but categorically denied reports that a pint glass was thrown.
"I was distressed to read reports about a glass being thrown, I witnessed the events myself," Devlin said.
"Karl Robinson was being escorted to the team coach, some of our fans were goading him and Karl Robinson reacted. There was almost an incident but our stewards stepped in.
"Some beer was thrown, most of which hit our operations manager and a couple of stewards.
"I can categorically say no glass was thrown at Karl Robinson.
"We have the police here at the moment and they are currently reviewing the footage from Saturday."
A Dons spokesman added: "We are aware of an incident at Griffin Park involving our manager Karl Robinson and a group of Brentford supporters.
"MK Dons will assist Brentford with their investigation into the incident, while this is ongoing it would be inappropriate to comment further."