Array of StringBuilders not working with P/Invoke

This was marked as a duplicate of Pass writeable StringBuilder array to C++ from C# but that does not at all address the issue of the use of StringBuilder[] and only comments on the incorrect use of wcsncpy and MarshalAs. I am not even using wcsncpy or MarshalAs anywhere in my question.

So, I'm trying to use one of my C++ functions in C# like this:

[DllImport("CPPDLLImport", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
static extern void StringBuilderArrayTest(StringBuilder[] text, int[] textLengths, int numberOfTextItems);

Now, normally this would work fine of course, but I'm don't think I'm getting the correct data in C++ from text.

So, in order to test this I set up a P/Invoke project.

I am calling the method in C# using this:

var stringBuilderArray = new StringBuilder[]
{
    new StringBuilder("abc"),
    new StringBuilder("def"),
    new StringBuilder("ghi")
};
var stringBuilderLengths = new int[3] { 3, 3, 3 };
StringBuilderArrayTest(stringBuilderArray, stringBuilderLengths, 3);

And this is my method in C++ - to test it I'm just printing it to the screen, and to make sure it definitely wasn't printf, I am literally printing it character-by-character just to be sure:

EXPORT void StringBuilderArrayTest(wchar_t** text, int* textLengths, int numberOfTextItems) {
    for (int i = 0; i < numberOfTextItems; i++)
        for (int j = 0; j < textLengths[i]; j++)
    printf("%c", text[i][j]);
}

And, well, the parameter text is definitely not right. It's just giving me "ÇPÿ" three times - definitely not the string "abc", "def" or "ghi".

Is it just not marshaling the StringBuilder array correctly? If so, how can I get this array of strings across?

UPDATE: OK, I have decided to use a string[] for sending data to my C++ code, however, I now need to do the reverse - sending data from C++ into C#. So, what alternatives are there to using an array of StringBuilder?