Have replicated this on 2 different computers, both recently upgraded to Big Sur 11.1 from the last version of Catalina (10.15.7 ?). The feature was working prior to the update, I used it within the last 48 hours on both.
Have tried both removing the alias in ~/Library/PDFServices (it was recreated on launch) and trashing and re-installing a fresh download copy ofScrivener from the L&L website. Didn’t work for either machine. Tried all of this with existing project files and new empty project files.
Don’t know what log files will be useful but happy to post any/all. I suspect something new in OSX has severed the connection between Scrivener and the PDF subsystem.