Why is your 1080p television showing 1080i?

HDTV is broadcast in two formats: 720p and 1080i. When your 1080p set gets these signals it has to convert them to 1080p. With 720p it scales the image to 1080p while with 1080i it deinterlaces the image. Current TVs are very good at this and so you wind up with the full 1080 lines of resolution in the end. If your 1080p is displaying 1080i on screen, it just means that is the signal it is receiving, but it is converted to 1080p before you see it.