InDesign adding blank pages at end of documents

I work on long documents. They are comprsed of an InDesign book, about about 50 or so different InDesign documents. Most of the InDesign documents have (and are supposed to have) an even number of pages. But at the back of the book are engineering drawings. While some contain an even number of pages, some contain an odd number of pages. 

I've recently started experiencing an issue where InDesign automatically is adding an extra blank page to the documents containing an odd number of pages. This happens across dozens of InDesign documents, used in about 2 dozen InDesign books. I have tried manually removing the pages, but they just keep reappearing.

I have tried exporting all the documents as IDML, then reopening them as INDD. But the issue persists.

I've been working on various iteriations of these documents for over a decade, and this problem just started last month. My workflow has not changed. I am using InDesign 2024.

What might cause InDesign to start determing that an even number of pages is required? And how can I turn this off?