I have my Xbox One plugged into my Sony KDL-32EX401 via HDMI. The settings on my Xbox are 1080p and Auto-Detect. My TV's screen settings are Wide and Full Pixel.
My problem is that my TV automatically resizes and overscans the image (i.e. Wide and Normal) randomly. This has really confused me as it doesn't happen on any of my other HDMI inputs (including an Xbox 360). Also, my TV screen settings are fixed and not on automatic itself, so why it automatically changes I don't know.
I've already tried changing the Xbox One's setting from Auto-Detect to HDMI, but this wasn't successful. A temporary fix is to go into the TV's settings and select Wide again even though it's already selected.
When the screen size changes, I also get a second or two of black screen.