Prince Andrew was also missing from the event.
The royal has spent weeks embroiled in a scandal surrounding his friendship with disgraced financier Jeffrey Epstein, who was arrested over his sex trafficking of underage girls.
According to the Daily Mail, Prince Andrew was spotted at a golf tournament just hours after reports surfaced of an argument between him and his senior palace aide.
A source told the publication that the Duke of York had "got very cross," but did not physically assault the aide.
"There were heated words on both sides but the altercation was in no way physical.
"It was a verbal dispute. It was a work-related issue. The Duke got very cross that what he wanted wasn’t possible."
A friend of Andrew’s ex-wife, the Duchess of York, also confirmed that Prince Andrew has "never assaulted anyone."
It was also reported that Prince Charles caught wind of the explosive fight and asked his brother to apologise.
"The Duke explained the situation to the Prince of Wales and left it at that. There was no apology because there was nothing to apologise for. The Duke maintains a good relationship with the Prince of Wales," the source said.
The Daily Mail also stated that an intervention from Prince Charles wouldn't be unusual.
An insider told the publication:
"He is the second most senior member of the family and is known to take action when and where is necessary.
"Mostly he is well informed and will intervene where it is appropriate to do so.’
Both Buckingham Palace and Clarence House have not commented on the incident.