Changing the value in debconf question in fontconfig also helped, correct?In my case (fontconfig 2.12.3-0.2, libfreetype6 2.8-0.2), setting FREETYPE_PROPERTIES was not enough. Only after I've also dpkg-reconfigured fontconfig to 'Full' hinting style everything got back to normal (pre 2.12 style).
I can confirm this. You need both full hinting in debconf as well as having FREETYPE_PROPERTIES set. Having only one of them does not do anything.