I need more information to help you with this issue. There are two main ways to view listings. There is the Guide, which can be set up in a large variety of ways and can be set to retain these settings quite easily, until the box is reset or loses power (Menu > Settings > Television > Last Viewed Guide State > Enable > OK > Exit). Then there are the Genres & Settings lists that are rather glitchy and can lose their settings each time the box is turned off.
So the questions are as follows: Are you talking about what you view when you press the Guide button, or what you view when you press the Right Arrow button? And when you press the Guide button, what does the Mode setting read at the bottom right corner? When you are viewing a channel and press OK, what does the Mode setting read at the bottom right corner?
For an overview of how these setting work and their limitations, go here.