This is a tracking bug for Change: Fontconfig cache directory change
For more details, see: https://fedoraproject.org//wiki/Changes/FontconfigCacheDirChange
The fontconfig cache files are placed onto /var/cache/fontconfig now. this seems incompatible with the ostree model. so this is a proposal to move it to /usr/lib/fontconfig/cache.
fixed in fontconfig 2.12.1-4
This bug appears to have been reported against 'rawhide' during the Fedora 26 development cycle.
Changing version to '26'.