At first glance, it looks like an embarrassing mistake. On 17 January, two Dentons lawyers sent a letter to CNN on behalf of Republican congressman Tom Price – President Donald Trump's nominee to be secretary of Health and Human Services – demanding that the news network retract an unflattering story.

However, it turns out that Dentons also represents CNN. A day later, Dentons US CEO Mike McNamara sent a letter to David Vigalante, CNN's senior vice-president for legal, apologising. The letter "should not have been sent by Dentons given our representation of CNN", McNamara wrote. "As such, CNN has no obligation to respond to the letter."

The Washington Post printed the letter from Dentons on its website, along with a story headlined 'Law firm withdraws retraction request to CNN over Price story'.

The Washington Post did not note it, but in what looks like a dollop of irony, one of the lawyers who represents Price – Atlanta-based litigator Randolph Evans – is something of an expert on conflict checks, writing multiple articles on the topic.

Hoisted by his own petard, right? Or not.

Dentons declined to comment on the matter and in an email, Evans said: "As noted in the numerous books and articles I have co-authored over the years, conflicts issues arise regardless of the size of the firm. Given my continued involvement with and Dentons' continued representation of these clients, however, I cannot comment on this particular matter."

In his writing, Evans has been clear that conflict checks are always essential – no exceptions. "As luck would have it, the one representation that escapes the system could be the one that creates the most problems," he wrote in an article last year for Legal Week sister title The Recorder.

So is that what happened here? He just forgot to run a check? It seems unlikely, and not just because you would expect him to practise what he preaches.

Campaign finance records show that Price, who represents Georgia's sixth congressional district, has been a longtime client of Evans.

As for CNN, is it plausible that Evans, a Trump surrogate who has appeared on the network and who works in the firm's Atlanta office, would be oblivious that Dentons also represents the Atlanta-based network?

This is doubtful. Dentons may be huge but the Atlanta office has just over 100 lawyers. And CNN is the kind of client that colleagues would mention. Even if Evans did not run a conflict check, you would think he would know.

So what did happen? Evans' own writing may provide an answer.

"In some circumstances, 'thrust upon' conflicts arise. It often involves a situation where a firm represents two different clients who suddenly have an unexpected potential conflict and there is insufficient time to address and/or resolve the conflict," he wrote. "More often than not, both clients have been firm clients without incidence."

So far, that seems right. Price and CNN were both Dentons clients, but they were not adverse to each other until the CNN story.

On 16 January, CNN's Manu Raju reported that Price "last year purchased shares in a medical device manufacturer days before introducing legislation that would have directly benefited the company".

That didn't go over well with the Trump transition team or Price, who is also represented by Benjamin Keane, a managing associate in Dentons' Washington DC office. They argued that Price had been working on the legislation long before his financial adviser bought shares of Zimmer Biomet, a company that would have benefited from the bill. The Dentons team also said Price didn't even know about the stock purchase at the time.

The initial CNN story ran two days before Price's first confirmation hearing on 18 January – which didn't leave the nominee time to shop around for new counsel. He needed to push back at CNN right away.

And indeed, CNN, while declining to retract the story, did make some modifications and updates to its reporting as a result of the criticism.

But back to what Evans wrote.

"On the one hand, the attorney cannot abandon one client at a critical time to that client's impairment. On the other hand, the attorney cannot pursue legal action against the other client. Until the attorney can extricate herself, the attorney should do her best to protect the one client while not pursuing affirmative legal action against the other."

So… you send a letter, you get the story changed – and then you say 'sorry, never mind'? Problem solved. Conflict averted.