https://bugs.freedesktop.org/show_bug.cgi?id=108086
--- Comment #5 from Mike Lothian mike@fireburn.co.uk --- So I think your distro uses the same build time for all their Mesa builds which means the cache is trying to reuse Mesa 18.1 shaders on Mesa 18.2
There's a fix to use the build-id on the mailing list, so hopefully this will be fixed properly soon