After every update of Edge, all PDFs open in Edge, not in PDF reader

Okay, and which setting specifically in Windows settings are you changing? Are you going into the PDF application and changing all the file types that a particular application owns, or are you going into the defaults by file type and protocol lists and changing the few that you want there? One other thing I thought of is that, if it's the second, it might be that you're missing something, and the PDFs are being opened in a different way than you're specifying.