I doubt that you are still facing the issue. I came to an understanding that kata needs a specific way to pass all tests. A simple prime generator wont cut it.
You need a class and to use the stream()

What you wrote there in your code is not 16M, it's 1.6M. Re-check how many zeros you put there.

"Passing a list as an argument passes a reference to the list rather than a copy of the list. Since lists are mutable, changes to the elements referenced by the parameter change the same list referenced by the argument."

Source: https://runestone.academy/ns/books/published/thinkcspy/Lists/UsingListsasParameters.html