There were reports Monday that Koepka and Johnson had to be separated after an altercation at a Ryder Cup afterparty, following the U.S. team's defeat to Europe in Paris. That followed comments made by Patrick Reed to The New York Times in which he said Jordan Spieth did not want to be paired with him at the Ryder Cup, later refuted by an anonymous teammate to the New York Post.
"This Dustin thing I don't get," said Koepka, at a news conference in Scotland ahead of the European Tour's Alfred Dunhill Links event. "There is no fight, no argument, he's one of my best friends. I love the kid to death and we talked on the phone Monday and yesterday and he told me how he thought.
"People like to make a story and run with it. It's not the first time there's been a news story that isn't true that has gone out. As far as the camaraderie [within the U.S. Ryder Cup team] it was fine, it was perfect. The problem is you guys try to find a reason why we lost and the simple reason is we didn't play good."
Koepka also reiterated his sadness after discovering the spectator that was struck by his tee shot during the Ryder Cup has lost the use of her right eye.
Corine Remande, 49, was taken to hospital after being hit by the shot, later telling AFP that a scan had revealed "a fracture of the right eye socket and an explosion of the eyeball."
"Yesterday was probably one of the worst days of my life," said Koepka, who also posted a message about Remande on social media Tuesday.
"There's nobody that feels worse about this than I did. It's a tragic accident what happened. I mean, I'm heartbroken. I'm all messed up inside. In my career it will be the one shot that I definitely regret.
"Everyone has assured me she's going to get the proper care that she needs and hopefully I can just speak to her because there's nothing more than I would love to do than just to talk to her.
"I wasn't told [about the extent of the injury] until I got to the golf course. When I got here and I had seven missed calls and 25 text messages I was like, 'What is going on?'"
"Then I was told the news and I'm really heartbroken, my stomach sank, yesterday was one of my hardest days of trying to focus and play golf just knowing what was to come when I was done.
"I probably spent an hour during my round on the phone trying to understand what was going on because it's hard to get the real story of what's going on, because I didn't know if it was fake or not. It's sad and I really am torn up about it."
Koepka added that the European Tour and PGA Tour are doing an "unbelievable job" setting up spectators for major golf events. The incident at Le Golf National has led to calls for golf's major bodies to review where spectators can stand on the course when attending future events.
"Unfortunately, you know, we can't always hit the fairway every time," Koepka said. "You know, that's the worst part. But they do an unbelievable job of where they set up, where they have people or just off the fairways, whatever it might be.
"The way the Tour, both Tours do it, is unbelievable. The saddest part is, it seems like every week almost, someone gets hit."
Tommy Fleetwood, a member of the victorious European team in France, admitted that he worries about the safety of his stepchildren when they stand alongside the fairway when watching him play.
"I sort of hate when my step-kids come and watch," Fleetwood said. "I say to Mo, who is 10, I say 'stand anywhere but where the ball could land, anywhere.'
"It can happen to anyone, and honestly, it actually surprising it happens less often than it does. You know, Brooks' shot wasn't that wide. I've seen the shot that it was. It's like ten yards left of the green. It's not that bad a shot, and it's really, really unlucky.
"I don't know what the answer is. Where they [Remande] were stood was the prime spot for watching on the green. I don't know what he [Koepka] can do, unless you give everyone a crash helmet before going on the golf course. It's just one of those things and golf is a bit of a dangerous sport in that sense."