Problems with input to a function that used RapidJson its AddMember function

I am trying to write a function that should check whether a member exists on a document. If it does it should remove the member and re-add it with a different value.

This is what I got so far (d is a rapidjson::Document):

void addMemberWithoutDuplication(std::string member, rapidjson::Value val) {
    if (d.HasMember(member)) {
        d.RemoveMember(member);
    }
    d.AddMember(rapidjson::StringRef(member), val, allocator);
}

This compiles and runs however the output is not as expected:

As shown rapidjson::StringRef(member) seems to be the cause of the question marks inside the boxes.

Reading these pages of the docs did not help me a lot:

• https://rapidjson.org/structrapidjson_1_1_generic_string_ref.html

• https://rapidjson.org/classrapidjson_1_1_generic_object.html

From what I read I should be doing it correctly but most likely my inexperience reading these types of docs is an issue here. Does anyone know what I am doing wrong or am missing?