No, the grammar police are wrong on this. Invested interest makes more sense and is not wrong. Vested interest would be wrong since her interest isn't vested, it's invested.

To explain better.

A vested interest implies she owns the result of what her interest is hence vested. She has a vested interest in the company performing well (because she owns shares of the company).

However, in this instance, interest in the subject I had brought up was an investment because it was her BF who would benefit from her sympathies (implying it would be systemic if more people thought like her) of what I was discussing with her and she would potentially benefit but it wasn't a sure thing because she doesn't own her BF so her interest was invested. In the context, a vested interest to the subject would imply she owns the benefits of her BF benefiting from a less oppressive society but she isn't certain of any benefit nor is she the owner of said benefits so her interest is invested not vested.

If she was a White male, she would have a vested interest but since she's a non-White Asian woman who was dating a White male, she doesn't have a vested interest, she has an invested interest.

No, the grammar police are wrong on this. Invested interest makes more sense and is not wrong. Vested interest would be wrong since her interest isn't vested, it's invested.

To explain better.

A vested interest implies she owns the result of what her interest is hence vested. She has a vested interest in the company performing well (because she owns shares of the company).

However, in this instance, interest in the subject I had brought up was an investment because it was her BF who would benefit from her sympathies (implying it would be systemic if more people thought like her) of what I was discussing with her and she would potentially benefit but it wasn't a sure thing because she doesn't own her BF so her interest was invested. In the context, a vested interest to the subject would imply she owns the benefits of her BF benefiting from a less oppressive society but she isn't certain of any benefit nor is she the owner of said benefits so her interest is invested not vested.

No, the grammar police are wrong on this. Invested interest makes more sense and is not wrong. Vested interest would be wrong since her interest isn't vested, it's invested.