Just when you thought you'd seen it all, another bizarre way to use USFM causes an issue. If a USFM file contains multiple \id elements, FileParatextProjectTextUpdater will produce an empty first chapter, with the USFM markers but no text -- the rest of the chapters are as expected. This seems to be due to _update_verse_rows_map being called once at the start of the book and again at the start of the first chapter, resulting in an empty list of rows to insert for the first chapter.

If you'd like, you can test this on the project ben_test_20251112 and the book of Ruth.

(By messing around with various combinations of \id elements and text after the book name, I was one time able to get it to output an entirely empty book, but I didn't dive into why that was)