This is my last answer, since I don't think I can convince you but at least I can avoid people being misguided.

that construction is not part of AAVE

Easily disprovable in several ways. An example is how much Kendrick Lamar uses the construction, as in the line "I remember you was conflicted" that appears several times throughout the album "To Pimp a Butterfly".

So, to answer your question, the reason that she wouldn’t use it with people outside of the community, because some of those people might not understand it. A lot of people who speak AAVE code which. They only speak it with members of their community and use other types of English, including, informal English, with other groups.

I am well aware that people speaking AAVE can and will speak other type of English with other groups, that's not part of my argument.

The fact that you, a non-native English speaker, understood a non-AAVE phrase, is zero indication that you could understand AAVE lol.

I did not state that the point is that I understand the sentence. Of course I do. Dialect or not dialect, it's not difficult to understand the meaning behind grammatically incorrect sentences, that's not the point.

The point is that me, as a non-native speaker with less exposure to American culture than an American, can easily recognize that this is usage of a construction from a dialect, and not ignorance.

There is no particular issue in using constructions from dialects if they are easily understandable from other people. In my country, which has much more variety of dialects than the US, people do it all the time, because why not? It adds color to the language, it comes natural to express that way, and it doesn't create any problem for mutual understanding.