Some good news for me, and for anyone else this happens to.
I had only updated one guy in the Town of Baron. The very first guy who appears in the code. I switched him back to his original text values, and all of the weirdness in the Town of Baron was undone.
I'm not sure exactly what happened, since my new text did not bleed over into the next text block. So, I wouldn't have expected the change to cause problems. But, whatever. At least I don't have to start over.
If anyone has any advice on ways to update townsperson dialogue without encountering this problem, I'm all ears!
Seems like townsperson dialogue is the only sticking point. I've reworked tons and tons of scenes and none of that editing has caused similar issues.