Update: Trump finally said early Friday -- as his campaign said late Wednesday -- that the video he saw wasn't of the $400 million cash transfer but of the hostages.

But the fact remains that he still talked about a video of the cash transfer even after his campaign said it wasn't of the cash transfer. The original post follows:

Donald Trump claimed Wednesday that he had seen video of the recently reported $400 million cash transfer between the United States and Iran -- this despite no video of the exchange being public or known about. His campaign explained late Wednesday that he was mistaken and had actually seen video of American prisoners being released by Iran, not the money transfer.

And yet, there was Trump on Thursday afternoon in Portland, Maine, recounting the very same nonexistent video of the money transfer.

"You know, it was interesting, because a tape was made. Right? You saw that? With the airplane coming in? Nice plane," Trump said. "And the airplane coming in, and the money coming off, I guess, right? That was given to us -- has to be -- by the Iranians. And you know why the tape was given to us? Because they want to embarrass our country."

Later in the very same speech, Trump brought up another story he often tells -- one that fact-checkers have determined is without merit -- that people saw bombs in the San Bernardino terrorists' apartment but didn't turn them in because they feared it would be viewed as racial profiling.

And less than a week ago, Trump again recounted seeing Muslims celebrating in New Jersey on 9/11 -- another well-chewed-over allegation for which there exists basically no evidence.

By now, it is well-established that Trump struggles with the facts, and he's prone to apparently inventing stories about things. But Trump's imagination is especially vivid and prolific when it comes to stories involving a specific topic: Muslims.

Yes, Trump has told stories before. Just a couple weeks ago, he recounted when Black Lives Matter protesters were "essentially calling death to the police." This, too, has been debunked, but it at least has some basis in reality. Protesters in New York City in 2014 called for the killings of police, but they weren't Black Lives Matter protesters, and BLM has disowned that rhetoric.

Similarly, he linked a protester at one of his events to ISIS -- apparently because of a hoax video.

And just this week, he noted that Harrisburg, Pa., looked like a "war zone," because it had so many closed factories -- this despite the economy in the Pennsylvanian capital being largely good, or at least better than much of the Rust Belt. Perhaps that's an easy mistake to make when you're touring economically distressed areas in the region.

But Trump's stories involving Muslims stand out in part because of (1) how utterly divorced from the available evidence they are, and (2) how much he keeps repeating them even after it's pointed out that they have no basis in reality.

And it dates back years. Trump's rise to prominence in conservative circles was largely due to his questioning of the birth story of President Obama. While the "birther" controversy was about where Obama was born, it is inextricably linked to questions about what Obama's true religion is, and many Americans who believe he was born in Kenya also believe he's a Muslim. Trump himself mused that maybe the birth certificate would say that Obama was a Muslim.

Back in 2011, Trump also recalled an apparently nonexistent video of Obama's grandmother saying she witnessed Obama's birth in Kenya. Similarly, he said he had an authoritative source that the birth certificate was a fraud.

But Trump's recollection of the Iran money transfer video on Thursday afternoon is perhaps the most flagrant example of this, given his campaign explained less than 18 hours prior that his initial story had merely been his mistake -- a misunderstanding.

The question is why. As I posited on Twitter after Trump brought up the nonexistent money transfer video, one explanation is that Trump is merely trolling us. He knew what his campaign said about the video, and he decided to cite it again just to get a rise out of the press.

If that's true, it's certainly a cynical strategy -- inventing stories about sensitive foreign policy matters in order to get the press in a tizzy.

Another is that Trump's campaign is a complete mess, and it never bothered to actually check with him when trying to explain away the video. If that's the case, it's also troubling, because it suggests the campaign has no message discipline and is lying to the press.

But if there's a topic on which Trump was going to double down without any evidence and in direct contradiction to his own campaign staff, it's perhaps no surprise that it involved Muslims.