I have seen the same tuner warning the OP noted multiple times, even when 1 tuner was needed. No AM-21 attached. Have not seen it in the past month or so.
However, I am running into an issue after watching a show on the HR34 when I try to delete it at end, it will say the program cannot be deleted (someone is viewing or something to that nature). As it was me that was watching it - then trying to delete, clearly this is a bug. When I immediately go to the program via the "list" button, I can delete it with no issue.