It seems the issue is due to suspend/resume. After resuming the system, I noticed the following entries in CUPS access_log:
localhost - - [10/Nov/2017:18:59:39 +0100] "POST /admin/ HTTP/1.1" 401 185 CUPS-Delete-Printer successful-ok localhost - root [10/Nov/2017:18:59:40 +0100] "POST /admin/ HTTP/1.1" 200 185 CUPS-Delete-Printer successful-ok and the printer is gone. I'm not sure what's performing the delete. ** Summary changed: - Installed printer disappears after a while + Installed printer disappears after suspend/resume -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1731417 Title: Installed printer disappears after suspend/resume To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/hplip/+bug/1731417/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
