Native resolution fails xfinity on-demand ! Bug?

Using my roamio basic i have native resolution output set. However I notice whenever I launch Xfinity on demand and start a HD video it will only play in whatever resolution I was using last before launching Xfinity. For example if I was watching live TV on Fox local channel 702 native 720p output formats and from there I launch Xfinity and play an HD movie it will play in 720p as shown when I press display button on my TV. However if I launch the same Xfinity video after watching a 1080i broadcast or program for my show list, the Xfinity video will be played in 1080 resolution.