It appears that creating files within guides/*.adoc causes errors.
The file is copies into guides/*.adoc as expected, but it is also copied into ./ which means the file is processed twice. The processing in ./ causes errors when linking to stylesheets since the stylesheets are not found
The docinfo-footer.html refers to the css, but it does not adjust based on the fact that the path is now guides vs ./ so the css is not found. A workaround is to use a custom docinfo-footer.html and use docinfofolder for sub directories.
It appears that creating files within guides/*.adoc causes errors.