Arsenal suffered the biggest upset of the third round as they embarrassingly lost 4-2 against the Championship outfit on Sunday.
And to make matters worse, Iwobi has now been caught on video screaming and dancing at 2.37am on Saturday before the match, according to the Sun.
The footage was posted on Snapchat and was captioned with “Shouldn’t Iwobi be sleeping?”.
The 21-year-old played the full 90 minutes on Sunday but failed to put in a good performance during a rare start.
Iwobi was partying at a rented Airbnb in Soho, central London, with friends.
And neighbours apparently complained about the noise, which did not stop until 3.30am.
One neighbour apparently told the Sun: “They were keeping everyone in the building awake.
“I was woken at 1am by chanting and singing and went to complain.
“There were laughing gas canisters all over the place and a strong smell of weed.
“They claimed they hadn’t been allowed into a club and that’s why they rented the flat.”
Arsenal have reportedly refused to comment on the situation.