A family of Microsoft word processing software products for creating web, email, and print documents.
I don't see anything you can do to restore the previous behavior, except to add your vote to the suggestion at https://word.uservoice.com/forums/304924-word-for-windows-desktop-application/suggestions/35041834-highlighting. If the person who posted that is correct, the current behavior is a mistake, so it might be possible to get it corrected in an update.
I'll ping the Word developers to be sure they're aware of it.