The article didn't point out any real problems with the credibility of the story
In addition to the one you addressed.
DEVGRU’s Red Squadron, together with their previous high-profile mission to kill Osama bin Laden. It must be noted, however, that the few available details about DEVGRU mention Red Squadron is an assault unit, while Intelligence, Surveillance and Reconnaissance operations, including clandestine intelligence gathering, are usually assigned to Black Squadron
The timing of the leak, coming just after Kim Jong Un’s recent high-profile appearance in Beijing with Xi Jinping and Vladimir Putin, adds another layer of intrigue
Also I would add about the helicopter. There is a huge difference in having a helicopter that can evade radar in an area with the world's most notoriously labyrinthine mountain valleys, from the exact opposite direction that nation expects an aerial attack, and having a helicopter that can evade radar over water, with zero cover, into a coastline where they would an expect attack from, in the vicinity of the North Korean equivalent of Camp David. (Admittedly, the also had to cross the Indus Valley, which would have had short exposure, but it would have just looked like a domestic flight at that point, and again, in the opposite direction they would expect an attack from)
The former is massively easier than the latter.
Helicopters have an external rotating part, that means that rotating part has to have a low radar cross section from every direction in the horizontal plane. In a deep mountain valley without any radars in that specific valley, that isn't as much of an issue.(It still is from above to some extent, but not as much of one, and Pakistan was unlikely to have a patrol with a decent radar on their northwest border) On a coastline, that makes it extremely hard, there is a reason all our stealth planes hide the fan blades entirely behind an S-Duct intake. So no, I don't believe we have a stealth helicopter that is likely to remain undetected on a well defended coast.
In addition, as one of the comments on the article pointed out, (I actually got it mixed up in my mind with the article itself
If this indeed really happened and N Korea knew about and had a smidgen of evidence of it, you would think that would blast it all over the news and media as much as they could.
Which the article does point out was a risk
Would DEVGRU (SEAL Team 6) really be tasked with a high-profile amphibious raid inside North Korea, and just weeks before nuclear talks in Hanoi?
In addition to the one you addressed.
Also I would add about the helicopter. There is a huge difference in having a helicopter that can evade radar in an area with the world's most notoriously labyrinthine mountain valleys, from the exact opposite direction that nation expects an aerial attack, and having a helicopter that can evade radar over water, with zero cover, into a coastline where they would an expect attack from, in the vicinity of the North Korean equivalent of Camp David. (Admittedly, the also had to cross the Indus Valley, which would have had short exposure, but it would have just looked like a domestic flight at that point, and again, in the opposite direction they would expect an attack from)
The former is massively easier than the latter.
Helicopters have an external rotating part, that means that rotating part has to have a low radar cross section from every direction in the horizontal plane. In a deep mountain valley without any radars in that specific valley, that isn't as much of an issue.(It still is from above to some extent, but not as much of one, and Pakistan was unlikely to have a patrol with a decent radar on their northwest border) On a coastline, that makes it extremely hard, there is a reason all our stealth planes hide the fan blades entirely behind an S-Duct intake. So no, I don't believe we have a stealth helicopter that is likely to remain undetected on a well defended coast.
In addition, as one of the comments on the article pointed out, (I actually got it mixed up in my mind with the article itself
Which the article does point out was a risk