I used “NYT” as the find and “New York Times” as the replacement hoping that I might correct about 30 instances of using just NYT. But my book manuscript grew from 164 pages to more than 300 pages, all of those extra pages saying “New York Times.”
You must have done something wrong. But we weren’t present when you did that and don know what replace pattern you entered. So, without more information from your side, we can’t help you.
The answer doesn’t get any better if you ask twice.
https://ask.libreoffice.org/t/writer-find-and-replace-created-150-pages-with-just-the-replacement/64540