Is this an inconsistency between Aquaman and Justice League?

Question

In the Aquaman movie, Mera told Aquaman that he helped save the world from Steppenwolf. It means that main events of Aquaman happened after the events of Justice League.

In Aquaman, we also learned that Aquaman had never been to Atlantis and it could even be dangerous for him to go there because he was a half-breed (Vulko and Mera were also trying to convince him to go there).

But, in Justice League, we saw that Aquaman somehow knew the location of Atlantis and that's how he tried to protect the Mother Box underwater. Even Mera was there at that time and she even talked to Aquaman (and yet, he didn't even know who she was in Aquaman?).

Are these inconsistencies? Or, am I missing something?

Answer 1

Long story short, what we saw in Justice League wasn't Atlantis, and if memory serves, Mera did not introduce herself either? Hence why Arthur would meet her in a more "formal" way in Aquaman.

Longer version is explained by an interview that director James Wan gave to the Huffington Post:

In “Justice League,” we thought Arthur Curry/Aquaman traveled to Atlantis when he meets Mera. But in “Aquaman,” he apparently goes to Atlantis for the first time. So what’s happening there? Where was he in “Justice League”?

It wasn’t Atlantis. I spoke with Zack [Snyder, director of “Justice League,”] early on, and Zack mentioned that the location that Aquaman swims to in “Justice League” is an outpost. So when he told me that was his idea, I was like, “Oh great, then I can actually have Arthur go to Atlantis for the first time.” That’s very important for me, because he can go into it and have a wide-eyed approach to Atlantis and be in awe of it. I think that’s very important from a storytelling standpoint because the audience gets to experience Atlantis for the first time along with the character.