@NiLuJe:
thanks for jumping in, I was actually silently hoping for your expertise
The weird thing is that the issue seems to appear undeterministically (geek term for "not reproducible"). Sometimes it works, sometimes it doesn't.
Could you give some more information about that custom freetype library thing? Am I right that replacing some .so file could fix this once and for all? If so, I'd be grateful for some pointers -- maybe I could simply include a working .so file with the installer (?)