You got a point, the only answer I can think of is that, yes, it wasn't supposed to happen, but the branched timeline it created wasn't a dangerous one, as it didn't lead to the creation of a variant of He-Who-Remains.

Basically, TVA only erase alternate timeline that could bring a variant of He-Who-Remains. All other timelines are allowed.

The Sacred Timeline is like a collection of safe timelines, more than a unique one, so I guess the Camp Lehigh timeline was a safe one and therefore allowed to exist by the TVA.

You weren't the only one with this question after Loki, don't worry. There isn't a clear and definite answer, only theories as to how it might work.

Loki raises a lot of potential inconsistencies with time travel rules.

Thanks so much guys!

You’re absolutely right. Unfortunately, this is one of those plotholes that only have an out-of-universe answer; the story couldn’t continue had the TVA arrested Steve and Tony so it couldn’t happen

Once, Loki Grabs the Space Stone it's cause a Branch Timeline and Since 2012 Loki wasn't going to give it back to 2024 Steve any time soon the TVA probably thought it would have been easier to just erase it then let Steve try to deal with it. Steve also can't bring back the 2012 stone so that Timeline can't be completely Pruned.

Also, I will Say this again, The TVA and He Who Remains are mostly Liars and they could have easily been lying about the Sacred Timeline all along.

You have a great point 👍! I actually wondered this myself, too after watching the movie 69,000 times. The answer isn't as simple as it may sound how I put it.

Ok, I could be wrong but I have a theory that sounds crazy. What if it wasn't Loki that created an alternate timeline- but instead the Avengers. You are right, they went to Camp Lejeune, after they failed in New York.

What if Loki WAS supposed to use the Tesseract and WAS supposed to go to the TVA. But that other timeline they talked about was actually that one the Avengers created by going to 1970 to retrieve the Stone.

My theory:

Hulk still hit Iron Man and caused the Tesseract to fall out. But instead of Loki grabbing it, a security guard (with special equipment) grabbed it first.

End result:

Loki doesn’t go anywhere, Avengers still need to go back in time.

The reason why is because the TVA stated they allowed the Avengers to change time

They could do it because they knew weren't going to mess up time

So this is why the weren't arrested

How did I never thought about this? I feel that Loki escaping with the Tesseract was a "necessary evil". You see the Avengers had this very intricate plan to retrieve the infinity stones, and so that they can succeed, in the exact way they did it, they kinda need to go through Loki stealing the Tesseract. But here's the thing, the 2012 timeline is already an alternate timeline on its own, separate from the "Sacred Timeline" or the main timeline, as we call it. For the TVA it was necessary for Loki to steal the Tesseract and allow the Avengers to go through their new plan, and stop Thanos. But once the Avengers already got what they needed (i.e. after Steve returns to deliver the Mind and the Time stones to the 2012 timeline), the TVA sees itself as having no need to see the 2012 timeline continue on its separate way. Loki, would be the catalyst for making the 2012 timeline different than the Sacred Timeline, so even though him stealing the Tesseract was necessary, whatever was about to succeed was deemed unnecessary for the TVA.

EDIT: I feel a more harrowing question would be how can Steve go back to the 1940s, and not get intercepted by the TVA. I have my own theory on this matter, but its also quite complicated when you consider the logics introduced in Loki.

Russos originally planned for a 6 hour endgame film, TVA arresting them would have been one HELL of a plothole.