access violation when calling self (C++, libtcod, Visual Studio 2019)

The function listener(TCODMap & map, Engine & engine) of my BSPListener class will never execute because calling *this as a parameter causes an unhandled exception error.(The call using *this is in initializeMap()).

In Engine.cpp

void Engine::initializeMap()
{
    float maxHratio = rand() % 10 + 1;
    float maxVratio = rand() % 10 + 1;

    int nbRecursions = rand() % 10 + 1;


    maps.push_back(TCODMap(70,40));

    for (int x = 0; x < maps[currentMap].getWidth() ; x++)
    {
        for (int y = 0; y < maps[currentMap].getHeight() - 1; y++)
        {
            //Set all cells to unwalkable and transparent
            maps[currentMap].setProperties(x, y, true, false);

        }
    }

    TCODBsp bsp(0, 0, maps[currentMap].getWidth(), maps[currentMap].getHeight());
    bsp.splitRecursive(NULL, nbRecursions, ROOM_MAX_SIZE, ROOM_MAX_SIZE, maxHratio, maxVratio);

    

    BspListener listener(maps.at(currentMap), *this);
    bsp.traverseInvertedLevelOrder(&listener, NULL);


    for (int x = 0; x < this->maps[currentMap].getWidth(); x++)
    {
        for (int y = 0; y < maps[currentMap].getHeight(); y++)
        {
            if (maps[currentMap].isWalkable(x, y))
            {
                std::tuple<int, int> temp = std::make_tuple(x, y);
                std::cout << "Valid spawn point at (" << x << ", " << y << ")" << std::endl;
                walkableCells.push(temp);
            }

        }
    }

}

In BspListener.h

bool visitNode(TCODBsp* node, void* userData)
    {
        //std::cout << "visited node";
        if (node->isLeaf())
        {
            int x, y, w, h;//w is width, h is height
            TCODRandom* rng = TCODRandom::getInstance();
            w = rng->getInt(ROOM_MIN_SIZE, node->w - 2);
            h = rng->getInt(ROOM_MIN_SIZE, node->h - 2);
            x = rng->getInt(node->x + 1, node->x + node->w - w - 1);
            y = rng->getInt(node->y + 1, node->y + node->h - h - 1);
            
            engine.digRoom(roomNum == 0, x, y, x + w - 1, y + h - 1);//Dont create corridor from nowhere if it is the first room

            if(roomNum != 0)
            {
                engine.dig(lastx, lasty, x + w / 2, lasty);
                engine.dig(x + w / 2, lasty, x + w / 2, y + h / 2);
            }
            lastx = x + w / 2;
            lasty = y + h / 2;
            roomNum++;

            
        }
        return true;
    }

I get this exception at listener()

Exception thrown at 0x00007FF8D032EFBB (ntdll.dll) in Huronia.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF.

Any ideas as to why this might be? I wasn't having this error when I was just using a single TCODMap object. Now that I've made it so we have an array of those objects, this simply doesn't work. All I really want to know is how I should go about changing the function.