I found my caveats file! It was actually an errant newline at the end of each file. Gnucash should've known enough to strip it. And the other thing was a file that used `--` for deposits, so I have a note to 's/--//g' those files.

I think that's the kind of thing that some of us see as a neat challenge to figure out and overcome; but for others, it becomes a barrier for entry. I still evangelize the heck out of Gnucash, though. It's so powerful...and not Intuit.