why does my 2d sprite keep setting itself to "Advanced" and don't pack ?

I have an image, I set it to to "Sprite 2d/uGUI", like all my other sprites, but when I apply, it switches to "Advanced". And then, even if I have proper Packing Tag setup, the sprites tagged with "Advanced" will not pack. My other sprites do not behave like that and pack properly.

Does anyone have an idea ?

Thanks !