Switching tuners with Live TV button stops working

I have a Tivo Roamio. I like to switch between tuners by pressing the Live TV button. The problem is that the functionality disappears from my Tivo after some period of time, at which point pressing the Live TV button I only see the channel info for the current tuner/channel.



Sometime I can go as long as two weeks before the function disappears, other times it is just a few days. A reboot fixes the problem for a short while, but it eventually stops working again.



any ideas?