Remembering a lunch date that happened more than 30 years ago isn’t easy. But then again, most lunches aren’t with Bill O’Reilly.

So late Sunday night, speaking on the telephone from his Florida home, former CBS correspondent Eric Jon Engberg found himself in a peculiar position. It was indeed true that once, in June 1982 while covering the Falklands war from Buenos Aires, he had shared a meal with O’Reilly. But how much did Engberg remember? Did he remember what O’Reilly had eaten? “This was more than 30 years ago,” Engberg told The Washington Post. “So, no.”

But Engberg, who spent weeks in Buenos Aires before O’Reilly arrived, remembered something else: O’Reilly’s braggadocio. There was a distinct sense of entitlement emanating from his lunch partner, he said, which struck Engberg as odd. The situation in Buenos Aires was deteriorating, and O’Reilly was young and green.

O’Reilly, however, wasn’t interested in tips. “I tried to give him some advice, give him a read on how the place worked,” Engberg told The Post. “He didn’t seem too interested. I offered him a suggestion on how things worked and he didn’t pay any attention to me. … I saw him as someone who wasn’t willing to be held back by the restrictions that govern rookie reporters — the fact you got to get up in the morning and go over to whatever briefing was going on and report it to your bosses and wait for your next assignment. He was the kind of guy who wanted to find a story that was going to get him on the air that night.”

O’Reilly and Engberg were in the news a lot over the weekend. On the one side, there was the Fox broadcaster who, following a Thursday report in Mother Jones, now faces allegations he inflated his war reporting bona fides after covering the Falklands war. Mother Jones noted that no American correspondent ever got down to the Falkland Islands, a point O’Reilly readily concedes.

“I was in Buenos Aires” when Argentina surrendered to the United Kingdom and gave witness to vast protests that quickly engulfed the capital, O’Reilly told The Post’s Paul Farhi. “Troops fired at the crowd. I was in the middle of that carnage.” O’Reilly added: “In Argentina, I was in combat in the sense that bullets were being fired.”

O’Reilly elaborated on his experience in April 2013 when he told the harrowing tale of how he saved his photographer, who “hit his head and was bleeding from the ear on the concrete. And the army was chasing us.”

But these assertions have now come under suspicion — which is when Engberg entered the drama. On Friday evening, Engberg posted 1,700 words to Facebook challenging O’Reilly’s claims. He said things never got that hot in Buenos Aires, calling the riot “tame.” “No one who reported back to our hotel newsroom after the disturbance was injured,” Engberg wrote on Facebook. “If a cameraman had been ‘bleeding from the ear’ he would have immediately reported that to his superiors at the hotel. This part of O’Reilly’s Argentina story is not credible without further confirmation.” The Falklands war, which began when Argentina tried to seize the British-controlled South Atlantic Falklands Island off the Argentine coast, lasted 10 weeks.

The drama is particularly fraught for O’Reilly. Earlier this month, as the Brian Williams controversy raged, O’Reilly, who normally has no problem marshaling moral indignation, went easy on the embattled anchor. “Every public person in this country is a target,” he told Jimmy Kimmel. “With the Internet — you know what it is, it’s a sewer. And these people delight in seeing famous people being taken apart. I just think it’s wrong. I mean, we’re human beings just like everybody else.”

The controversy also provides a sharper glimpse into a pivotal chapter in the Bill O’Reilly narrative: his brief, dramatic tenure at CBS. It was the moment when O’Reilly’s ambitions collided with his rookie status.

O’Reilly started out small on the local TV circuit: Scranton, Pa., Dallas, Denver, Portland, Ore., and Hartford, Conn. Then CBS came calling. This finally seemed O’Reilly’s big break. He was going to be filing footage for the great Dan Rather.

“But it didn’t work out,” Nicholas Lemann wrote in the New Yorker. “… The CBS episode has stayed with him. It hurt — it still hurts. No matter how big a star he becomes, he’s eternally the guy who was banished from the charmed circle. O’Reilly’s account of what went wrong at CBS has him, as always, pissing off powerful people because he won’t play their phony games.”

It may be more complicated than that. The way O’Reilly tells it in his best-selling book “The No Spin Zone,” things went wrong in Buenos Aires from the beginning. “I was told there would be a CBS driver to meet me and guide me quickly through customs,” O’Reilly recalled, still burning over the slight decades later. “Guess what? Nobody showed up. I was beginning to see a pattern.”

It came to a head when O’Reilly and his cameraman captured what he called “the best news footage I have ever seen.” O’Reilly, in claims now questioned, said there was “a major riot” in Buenos Aires, and “many were killed. I was right in the middle of it.”

When O’Reilly filed the footage, he thought he had nailed it. No doubt he would lead Rather’s newscast. “Nope,” O’Reilly wrote. “In perhaps the most stunning thing that has ever happened to me, all the videotape was taken away from me and given to a big-name correspondent.”

Engberg, however, wrote in his post that O’Reilly was overreacting to a routine editing decision. When a superior “informed O’Reilly that [Bob] Schieffer would be doing the report, which would not include any segment from O’Reilly, the reporter exploded. ‘I didn’t come down here to have my footage used by that old man,’ he shouted.” (Schieffer would have been about 45.) O’Reilly was soon sent home, Engberg said, called a “‘disruptive force’ who threatened his bureau’s morale and cohesion.”

The squabble intensified in New York, commented retired CBS national editor Sam Roberts in a Facebook thread beneath Engberg’s Facebook post. Roberts said he was told to turn O’Reilly into a “real CBS News Correspondent,” but Rather had deep reservations.

“Dan Rather walked into my office and shut the door,” Roberts wrote. “He said, ‘Under no circumstances is O’Reilly to be assigned any story for the Evening News. I sat O’Reilly down and said something to the effect that he was like the All-American football player who got drafted by the Dallas Cowboys and brought all of his press clippings to training camp. ‘Nobody gives a s—,’ I said. ‘You’ve got to do it here.’ ”

A few weeks passed, and Roberts’s phone rang. It was O’Reilly’s agent. He wanted to know how O’Reilly was doing. A station in Boston had offered a job to O’Reilly — should he take it? Roberts: “‘He’ll never make it here,’ I said. ‘Take that job in Boston before it goes away.’ And that was the end of O’Reilly’s career at CBS News.”

And it was to remain that way — gone, forgotten — until now.