I tested this at length this morning, and I find that while it appears to return results, it does not seem to do so reliably across file types. I’m guessing there is a bug persistent somewhere, as I kept getting rtf and txt file results that showed up as results, yet would not show in-file results even though they should have based on more simpler searches for the same basic terms.
The syntax you shared does seem to work as expected with PDF files, however.