Hi Eibert,
With Acrobat 11.0.8, I've verified on 3 physical printers (HP, Xerox, Samsung) and it's working fine.
But as per my observation, After flattening and printing at Acrobat side, it's the printer which is taking time to give actual printout.
This behavior is seems like printer related not the Acrobat specific.
Please do the following scenarios..
1. with the same printer, in the pages to print option -> give a page to print , please verify !!
2. printing from web browser http://www.voordeelmuis.nl/sample.pdf
3. if possible, try with other physical printers.
please reply your observations !!!
Best regards,
Anil