I've got a Plus with a Moto M-card running 6.25 firmware. Have had no issues with all 6 tuners in the month that I've had it until last night - a scheduled recording of Nature on one of our local PBS stations failed with 'not authorized' reason given. I saw the failure and tuned the channel just fine in live TV, and it subsequently recorded the repeat overnight without issue.
Is this another tuner issue with the Roamios, a possible card issue, or just a glitch? I've had no signal level problems that I know of.