Regarding the "conf.d"-advice: This was more meant for debugging a service in general for the future, giving therefore you a helping hint how to do that. In regards for cups: I assume you are using stable-branch. So this was solved some time ago as a Debian-patch given the wrong configuration-statement included. You can therefore rebuild cups for the moment on your own with the files here: https://git.hyperbola.info:50100/packag … /tree/cups
Just download all included and go on with "makepkg -s" than in the corresponding folder.
The patch being removed is to be find within the PKGBUILD:
rm -v debian/patches/0006-Debian-Set-LogFileGroup-to-adm.patch || true
So you have already found the error on your own and that is what to be reached as no one can now take this knowledge away. Thanks for debugging! With upcoming 0.4.3-release this is already solved.
Human being in favor with clear principles and so also for freedom in soft- and hardware!
Certainly anyone who has the power to make you believe absurdities has the power to make you commit injustices: For a life of every being full with peace and kindness, including diversity and freedom. Capitalism is destroying our minds, the planet itself and the universe in the end!