Its not asking you to change the channel, its alerting you it needs to change channels on either tuner to record a show. It won't alert you if the tuners hasn't been changed after 1/2 hr's inactivity. On the current tuner, it will alert you as it wants to change the channel to record if the other is currently being used, you can select 'change the channel' or 'don't change'. You can also press CLEAR to clear the message and to select to change.
Series 2 (PLS, sold)
TiVo HD 1TB (157 HD Hrs, PLS, "652")
Roamio! Oh, wait, Its Juliet!
OTA! OTA! OTA!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!