TM missing previous translations

I'm translating a book, and one chapter is based on a set of translations I already did last year (as a single file project, using my master TM). However, when I'm in the editor working on the book, it is not populating target fields with the translations. Even when I do a concordance search, it doesn't find the old translation of any segments. I have the master TM enabled. I'm using Studio 2021 on a PC (Windows 11). I think when I did the previous translation, it may have been before I upgraded from 2019 to 2021.

Obviously, I have my old translation in a Word file, but it's long, and I'd like to figure out why it's not already incorporated into my TM rather than pasting all of it segment by segment into my current file. Any help would be appreciated.

emoji