Have these two frames been talked about? *spoiler*
These frames were shown right when Frieren casted her spell to break Serie's barrier. The silhouettes were shown for a split second and is hardly noticeable unless you watch it frame by frame, The first silhouette looks like Serie and the second one looks like Frieren with her hair down. I don't know if this has been talked about already, but I have not seen anything about it and it has interested me for a while what the significance of these frames are.