Shutdown hanging due to cups service

I thought the bug fixes in https://bugs.launchpad.net/ubuntu/+source/cups-filters/+bug/1579905?comments=all and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=832637 could have fixed the shutdown hang problem due to CUPS. But people on Stackexchange (https://askubuntu.com/questions/760952/slow-shutdown-on-ubuntu-16-04-lts-stopping-thermal-daemon-running-fit-make-remo/896655?noredirect=1#comment1468203_896655) was still reporting the same issue. I don't know what's the problem and this issue doesn't occur on me, but I'd like to make a report here and guide people on Stackexchange who has this issue to report on what they have seen.

Hopefully, this shutdown hanging issue will be completely fixed soon!

Thanks!
Qi