Hello Pode, there is a serious bug with this behavior.
After Load image from URL and detect face, the answer will be correct.
BUT BUT BUT upon load image from URL [because say the Sprite is reloaded with a new image, we are assuming a sprite with one picture here so no complication].
When executing detect face, it will gave the answer from the previous result, and no matter how many time in the future you refresh the Sprite using LoadFromURL, the answer given by this plugin will ALWAYS be the answer from the First Initial call to detect face!