I just picked up a new Roamio 6-tuner TiVo in order to test out and post a review of soon. It is my 7th or 8th TiVo I've ever owned, but this one has proven problematic on setup due to a bug with Verizon FiOS, CableCARDs, and pay channels.
The problem looks like this on any channel that isn't a major TV network:
I went through a couple back and forths with Verizon tech support (who insisted this was a bad coax or HDMI cable issue) and eventually @brennokbob on Twitter pointed me to a thread on the TiVo Community forum where a user reported similar issues with HBO not working on their new Roamio TiVo on FiOS. Design VP of TiVo Margret Schmidt pointed out the issue is with CableCARDs that aren't the latest and greatest version.
My own multistream CableCARD is two years old (shown below), and carries one of the "bad" serial numbers listed in those posts, so I'm getting scrambled cable on my new TiVo until a technician can help me replace it.
Hopefully anyone else with a similar problem stumbles onto this post and can get it remedied.