This is a problem that was introduced with the newest firmware, released a month or so ago. Everyone with a box was automatically upgraded, or else they wouldn't be getting any TV right now.
If you call the call center, they won't be able to help you, other than they will suggest that if you want the bug team to prioritize it, go to
this page and submit feedback, so they know that it is bothering a lot of people.
Other bugs I know of are if you are in the search by title screen for a long time, it will leave the screen and change your channel (I think to channel 2)