Sometime today Firefox decided to look for any PDF on a page I'm on and automatically download it and then open it on Adobe. Looking at a page with a PDF owners manual or something similar will instantly trigger the download once the page fully loads and open the PDF. I have run in troubleshooting mode and this still happens.

My current, and temporary solution has been to select the "Always Ask" to at least stop the download. Doesn't happen in Chrome and my default PDF viewer is set to Windows and is Adobe.