Confusing Shortcuts error says file can't be opened because I don't have permissions to view it but I actually do

I'm running Sequoia 15.0.1. I have a Shortcut to get the most recent file from my Downloads folder, email it as an attachment to a certain email address, then delete the file from the Downloads folder.

I'm now getting an error message on the first step of the Shortcut: "The file couldn't be opened because you don't have permission to view it."

Uh, I do have read/write access to my Downloads folder and to the downloaded PDF file that this Shortcut should be getting and sending. I can certainly open the PDF with a double-click.

The Shortcut was working fine a month ago.

What's the problem and how to fix it?