Just noticed this last night and while it isn't a big deal it's a bit odd.
I was changing the volume with the included 1070 remote and immediately after turning the volume up or down a few notches (i.e. holding the button down) if I pressed a button on the TiVo remote (again, the stock remote shipped with a Series2 TiVo) it would duplicate the volume adjustment on the 1070. I tried this a few times pressing the volume down or volume up button and then switching to the TiVo remote and pressing play or the 5 second jump-back button and it kept working, but only for a few seconds.
The TiVo remote is set up to work my TV, but not the 1070 (since, unfortunately but expectedly, it doesn't have the codes and I can't auto-discover any codes that work for it) and the buttons I were pressing were exclusive to the TiVo anyhow. It worked for different codes being sent and was duplicated on the TiVo remote when I used different buttons there as well.
Frankly it just sounds like some sort of signal interference or something and may or may not be fixable (I'm leaning towards the latter), but I thought I'd mention it anyhow. Personally, even if it was fixed with a firmware update I probably wouldn't consider it worth the effort to drag my 1070 over to the computer and update it until I need to pull it out for some other reason.
Still, an interesting phenomenon and one I've not previously experienced with any other equipment.