SDL2 images appear warped on edges of window when using BlitScaled()

The title says it all. Images are warped on the edge of my window when I use SDL_Blit_Scaled(). here is a picture of the issue

those black lines are not supposed to be there. It seems to be reading part of the next sprite in my sprite atlas:

idk why this is happening. when I render a sprite to the screen I run this function in my custom class:

const int GameObject::draw(SDL_Surface windowSurface, Camera& camera)
{
    if (edge(1) - camera.posX + (camera.windowWidth / 2) < camera.windowWidth && edge(3) - camera.posX + (camera.windowWidth / 2) > 0 && -edge(4) + camera.posY + (camera.windowHeight / 2) < camera.windowHeight && -edge(2) + camera.posY + (camera.windowHeight / 2) > 0)
    {
        SDL_Rect rect = { (id - 1) * imgWidth, (type - 1) * imgHeight, imgWidth, imgHeight };
        //SDL_Rect dstrect = spritePos(posX - camera.posX + (camera.windowWidth / 2), -posY + camera.posY + (camera.windowHeight / 2));
        SDL_Rect dstrect = { edge(1) - camera.posX + (camera.windowWidth / 2), -edge(4) + camera.posY + (camera.windowHeight / 2), scaleX * imgWidth, scaleY * imgHeight };
        SDL_BlitScaled(&imageSurface, &rect, &windowSurface, &dstrect);
    }
    return 1;
}

GameObject.h:

class GameObject
{
public:
    const int draw(SDL_Surface windowSurface, Camera& camera);

    int edge(int dir)
    {
        if (dir == 1)
            return posX - (imgWidth * scaleX) / 2;
        if (dir == 2)
            return posY - (imgWidth * scaleX) / 2;
        if (dir == 3)
            return posX + (imgWidth * scaleX) / 2;
        if (dir == 4)
            return posY + (imgHeight * scaleY) / 2;
    }

    int id = 6;
    int type = 2;
    int imgWidth = 10;
    int imgHeight = 10;
    int scaleX = 10;
    int scaleY = 10;
    int posX = 0;
    int posY = 0;

    SDL_Surface imageSurface;

    //other stuff that's not relevant in this context
};

yes ik that the "edge" function is in the .h file instead of the .cpp but im too lazy to deal with it rn. any help is appreciated!