I experienced the same problem.
As i only need to print a PDF as A3, i got this solution:
Go to the Preferences of your Adobe PDF Printer, via Control Panel -> Printers & Faxes.
There at the General tab you click on the "Printer Settings" Button.
At the Dialog at the tab Adobe PDF Settings you choose A3. Click OK.
At the Preferences-Dialog you click on the tab Device Settings. There you also choose at OnlyOne: A3.
I think you now will have the problem all again, but contrary. You will have to print twice that you get A4 or any other size than A3...
It behaves like a bug, yes.