postinstall: fontconfig abnormal exit

[Fergus Daly]

Sorry if this has been asked 4 million times already.
During postinstall, both at ground-zero installation and at every update thereafter, and for both Cygwin-32 and -64,
(both using the appropriate setup-x86[_64].exe) I get:
running: {pathToCygwin}\bin\bash.exe --norc --noprofile "/etc/postinstall/fontconfig_dtd.sh"
abnormal exit: exit code=2
Is there something that can be done to address this "error", if that is what it is, or is it just a quirk of setup?
Thank you!