Arsenal boss Arsene Wenger told fourth official Anthony Taylor he was "dishonest" shortly before pushing him against Burnley, according to the referee's report.
Wenger was given a four-match touchline ban and £25,000 fine in January after he was charged with misconduct and using abusive and/or insulting words toward the fourth official.
The Arsenal boss had been protesting an injury-time penalty that was awarded to Burnley before his team snatched a 2-1 win in the 98th minute through Alexis Sanchez.
Cited in the "written reasons" released by The FA, match referee Jon Moss wrote in his report after the game: "In the 92nd minute of the game, following the award of a penalty against Arsenal, I was informed by Mr Taylor that he had been confronted by Mr Wenger in the technical area.
"He informed me that despite being warned to consider his conduct, Mr Wenger stated to Mr Taylor 'You are dishonest to your federation!' Mr Taylor told me that he told Mr Wenger that this was not acceptable to which Mr Wenger replied 'F--- off'."
Taylor's postmatch report included further detail, including the physical confrontation.
Taylor wrote: "Following the award of a penalty kick against his team in approx. 92nd min, Mr Wenger left his technical area to confront me in disagreement at the decision. Before he said anything I said 'think carefully before you say anything'. He responded by saying 'you are dishonest to your federation'.
"I considered this to be questioning both mine and the referee, Jon Moss's integrity and impartiality. I stated to Mr. Wenger that such a comment was not acceptable and he told me to 'f--- off' on two separate occasions.
"Once Burnley had taken the penalty and before the game restarted I informed the referee, Jon Moss, what Mr Wenger had said and he subsequently dismissed Mr Wenger from the technical area. Initially Mr Wenger wanted to return to his technical area and I had to ask him again to leave the vicinity as required.
"He then chose to stand at the opening of the tunnel. I again approached him and asked him to go to the dressing room area. At this point Mr Wenger pushed me twice and I had to ask the security staff present to escort Mr Wenger to the dressing room area.
"At the conclusion of the match Mr Wenger visited the officials changing room and apologised to myself and Mr Moss for his earlier actions."
The FA also said that Wenger had told the Independent Regulatory Commission that was reviewing the case that he "thought [he] could go to the tunnel and watch the game from there" and that "nobody had given [him] instructions as to where [he] ought to go," but this was rejected as a letter had been sent to all Premier League clubs.
Explaining the push, Wenger also said he acted "instinctively" when the fourth official had raised his arm to indicate he should leave the tunnel area as he felt his personal space had been invaded.
However, he said he visited the officials in their dressing room after the game, explaining: "My behaviour was not what I expect of myself."
There had been calls from prominent former referees for Wenger to receive a more severe punishment, but the Commission said it had taken into account that the Arsenal boss had accepted the charge early and apologised to the officials both publicly and privately, and that "he should be credited for his excellent disciplinary record prior to these charges being brought against him."