A thousand words suddenly missing

I have LibreOffice Writer version

I have an English language manuscript. Yesterday I broke 40 000 words and saved the document. This morning when I opened it, my word count was at 39 084. Where did almost a thousand words go? I can’t see anything missing in the document, and this smaller word count is in all versions I saved yesterday.

I don’t have any footnotes or styles or such things, just basic text.

To make matters even stranger, I opened the document in OpenOffice. It shows a word count of 39 099.

Thanks to anyone who can help solve this mystery!