How can I understand/detect/correct this pasting issue in Microsoft Word?

I have encountered some strange behavior pasting certain text into Microsoft Word 2016. If I paste page 21 of this document into Word, all of the text between the first two instances of the < (not ≤) character on that page is replaced by a single < character. Similarly weird behavior occurs around other <. If I paste and Keep Text Only, the missing text appears, but my purpose for pasting into Word is to alter the formatting in such a way that my TTS reader puts pauses in desirable places, and Keep Text Only reinserts unwanted line breaks. Using paste and Keep Text Only, then replacing all ^p with a single space mostly solves the problem, with only the occasional undiagnosed strange behavior remaining.

Why does this behavior occur, and is there a more targeted workaround than using Keep Text Only when pasting a document which may contain many such instances?