Whew
Yeah
.
However, what I ran into here does bring up a few points / questions:
I figured out how to fix it partially by changing the tuner priority. I swapped the priority of the first and second CableCard tuners and JRiver then happily tuned a channel for LiveTV. Before swapping the tuner priority, why did JRiver not try the 2nd, 3rd, and so on priority tuners rather than just giving up after it was unable to use the first tuner? Same thing with a recording - based on the logs, it simply gave up rather than moving on to the next tuner in the list (I have a total of 9 CableCard tuners - 3 HDHomeRun boxes).
I also noticed another issue while investigating this. In TV Options > Advanced > Show status, only the first 14 tuners are shown and there's no scrollbar to see the status for the remaining tuners (I have a total of 35 tuners, 26 OTA and 9 CableCard). There is the option to use TV Options > Advanced > Copy television filter related info to clipboard, but it would probably make sense to add a scrollbar to the Show status popup for those of us who are crazy enough to have more than 14 tuners (and actually part of the info for tuner number 14 gets chopped off). In case it matters, I've got the Windows desktop resolution set to 4K and setup to display at 200% so it's easier to read.
Finally, I have sometimes noticed a message in the logs that includes "putting tuner into an error state". What does that actually mean and is there a way to clear that state?