Update: After inadvertently triggering its Metal Gear Solid 5: The Phantom Pain 'nuclear disarmament' event earlier this month, Konami has now explained what happened and has apologised to its players.
As detailed in the following tweets, the publisher says its servers were fed "incorrect values", which in turn forced a false player-owned nuke reading.
Moving forward, Konami has applied "a series of counter-measures" to prevent this from happening again, however does not go into detail as to what they are.
We have implemented a series of counter-measures during today's server maintenance to resolve this issue and prevent this from happening in the future. We apologize to all our players, and thank you again for your patience. (2/2)February 13, 2018
Our original story follows.
Metal Gear Solid 5: The Phantom Pain has a special, very-briefly-secret event that was set to trigger if, and only if, all of the nuclear weapons in the game have been removed. It first came to light thanks to the efforts of dataminers, and Konami confirmed it a few months later. On February 2 the event was finally triggered, rewarding players with a cutscene memorializing the accomplishment. There was one problem, however. It wasn't supposed to happen.
The nuclear disarmament event was triggered in the Steam version of METAL GEAR SOLID V: THE PHANTOM PAIN on Feb 2nd at approximately 12:00 GMT. We are still investigating, but can confirm that the event was triggered while the nuke count hadn’t reached zero. (1/3)February 4, 2018
The good news is that nothing appears to be broken, but at the moment it's still not clear what set it off. "We will share more information as soon as possible, but you can play the game normally and other platforms have not been affected," Konami said in follow-up tweets.
"We would like to apologize for the inconvenience and reassure you that we will investigate the matter as well as take the necessary action to avoid this in the future."
Nuclear disarmament is a noble goal but as Ars Technica pointed out, efforts to reduce virtual stockpiles have so far (and entirely unsurprisingly) run up against players who get a giggle out of fueling the arms race. Which would fit with a theory retweeted by fan site Snake Soup: That players have created so many nukes since MGS5 was released that it broke the game.
Actually based on the number of nukes being 2,147,483,647(maximum value for Int32) we're leaning towards the stack overflow theory. https://t.co/nXbdPeGr3NFebruary 2, 2018
But another theory suggests that it may have been a hack gone wrong that set things off. The MGS5 Nuke Watcher site indicates a very sudden and precipitous decline in the number of nuclear weapons in the Steam version of the game (although it still far outstrips what PS3 players have managed to amass), which could indicate that shenanigans of some sort are afoot.
The fabled no-more-nukes trailer is below.