Missed recordings at random times because shows "no longer appear in the guide"
I have a fairly new TiVo Premiere Elite (bought on Woot a couple of months ago and hooked up about 6 weeks ago) with an M-Stream CableCARD from Optimum/Cablevision and over the past week since setting up new fall TV season recordings (not season passes, just recording from the "By Channel" option about a week ahead of time), I've noticed a bunch of shows not being recorded, and when I go into the recording history, it says that the program wasn't recorded because "it no longer appeared in the program guide". This happened more than a few times and really concerns me.
I have another TiVo, an HD model that's about 4 years old, and it doesn't have the same issue. I set up the same recordings on that one the other day as a test and all of them recorded just fine even as the Premiere failed multiple times. So I don't think it's a problem with the actual guide data or my Optimum account.
Last night, one minute into a failed recording, I noticed that a show wasn't recording that should have been, so I turned to that channel and the bar at the top properly showed the name of the episode, and the show was playing properly. I hit the record button and it recorded just fine.
Also, at random times Sunday night during the football game, my NBC HD station flashed and started showing me programming from an NBA channel (I was still on NBC). The SD NBC channel still had the football game, though, and a few minutes later, the HD channel went back to the football game also. That was very strange. None of my friends had that issue.
At this point, I believe I've narrowed it down to a TiVo issue (hardware or software), a CableCARD issue or a signal/line strength issue (the technician recently installed new wires and tested them for signal strength, and until 6 weeks ago, the TiVO HD was hooked up to that same line and didn't have the same problem so I doubt it's that). My next step is to replace the CableCARD but I figured I'd ask for community expertise first. I'm also considering leaving Optimum for FiOS for unrelated reasons but I don't want to do that just yet if it's my TiVo that's a problem.
Any thoughts? Anyone experience this issue this regularly? I've now missed (or almost missed) 8 shows in a week on various nights and this can't continue!
Thanks in advance for your help.