The 22-year-old and Alejandro Garnacho have been spotted showing their middle finger towards fans while in Malaysia for the club's post-season tour.
In a clip shared to social media by one fan, Amad can be seen heading past supporters shouting his name.
He then extends his right arm with his middle finger raised in a gesture seemingly directed in the direction of the local supporters.
In a separate incident, as he gets off the Manchester United team bus he can be seen making the X-rated gesture again.
Amad says he raised his middle finger after he was subjected to personal abuse from fans.
The winger took to social media to address the exchange, revealing he had been subjected to insults about his mother.
He said as cited by Sports Central: "I have respect for people but not for the one who insults my mom… I shouldn't have reacted like that but I don't regret what I did. We had a great time in Malaysia with good people."
Garnacho has also been seen making the gesture.
After Man Utd's first game of the tour the 20-year-old - who has been told to find a new club by boss Ruben Amorim - was seen sticking his middle finger up at a camera as he walked off the pitch.
Meanwhile, in a separate snap, a group of Man Utd players that included Amad and Garnacho are seen posing for a selfie with a pair of fans.
The duo are seen with sombre facial expressions showing their middle fingers while standing at the front of the group photo, which also contained Joshua Zirkzee and a number of United youngsters.
It is not clear what the wider meaning behind the pose is, though the consistent use of it suggests it might be an inside reference in the Man Utd camp.
SunSport have gone to Man Utd for comment.
A separate fan interaction had seen Amad, Garnacho and Ayden Heaven asking locals to help them pay for some Beam e-scooters to take in the city.
While Garnacho cast a glum look at a shirt signing event.
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