You just never know when MythTV is going to do something goofy. It is the best option I’m aware of but it isn’t without it’s quirks. Periodically something goes haywire and this time, I ended up with screwed up database tables, apparently.
Fortunately, this isn’t an entirely uncommon issue. I found some info at pantz.org. There’s a process to run to fix tables. But you have to ask yourself, if the system knows that tables are crashed and has a script to fix them, why do I need to be involved to tell it to fix them?