On Windows only
While printing a PDF from Acrobat DC or Acrobat Reader DC, even though the Choose paper source by PDF page size option is selected in the Print dialog box, the document gets printed with the default page size.
Update your Acrobat DC and Acrobat Reader DC. The latest patch release has the fix for this problem. To update from within the product, open Acrobat or Acrobat Reader, and go to Help > Check for updates.
If you have disabled the Protected Mode in Acrobat DC or Acrobat Reader DC as a temporary workaround, enable it back after upgrading to the latest patch (21.001.20138 or higher) by going to Edit > Preferences > Security (Enhanced), and select the option Enable Protected Mode at Startup.