Kia Orana Katoatoa,
don't we just all love it when someone somewhere thinks of an improvement, forces it upon the unsuspecting user and doesn't even bother to ask of the user wants this feature?
Enter the pesky 'Choose paper source by PDF page size'
in Acrobat Reader Version since somewhere along Version 10 and later:
nice idea but not when the printer has a feature to then ask for the paper to be put in the manual feed and in addition has very little in the way of buttons to then stop the print job from blocking all future print jobs then this feature is backfiring.
If tick 'Choose paper source by PDF page size' this will override the paper size of your current default printer to whatever paper size was set when the PDF file was created (i.e. U.S. sizes of 8.5x11 inches if you receive an invoice from an American Supplier")
If you untick 'Choose paper source by PDF page size' then Acrobat Reader will just use the paper size that is default in your default printer (this should almost always be A4) and you can then choose Fit, Actual Size, Shrink oversized pages or custom scale in the same print dialogue to scale the document to the page size of your printer. Fix is the recommended default option.