this is not confirm-able and seems to be a local issue I'm still working out where it lies. This is not however a grave bug affecting this package version as originally suspected. If there is a bug at all its related to reinstalling after purge and rm -rf of all config dirs and hplip.conf not being reinstalled even with --force-confmiss.
root@debian:/home/roger# apt --reinstall -o Dpkg::Options::="--force-confmiss" install hplip Reading package lists... Done Building dependency tree Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 1 not upgraded. Need to get 145 kB of archives. After this operation, 0 B of additional disk space will be used. Get:1 http://mirrors.edge.kernel.org/debian stretch/main amd64 hplip amd64 3.16.11+repack0-3 [145 kB] Fetched 145 kB in 0s (256 kB/s) (Reading database ... 281784 files and directories currently installed.) Preparing to unpack .../hplip_3.16.11+repack0-3_amd64.deb ... Unpacking hplip (3.16.11+repack0-3) over (3.16.11+repack0-3) ... Setting up hplip (3.16.11+repack0-3) ... Creating/updating hplip user account... Can't open /etc/hp/hplip.conf: No such file or directory. Can't open /etc/hp/hplip.conf: No such file or directory. Processing triggers for man-db (2.7.6.1-2) ... Processing triggers for dbus (1.10.26-0+deb9u1) ... this is an local issue and not a bug unless you'd consider the failure to generate this config file or it missing causing this issue, a bug