Not a bad idea, but I can confirm this is NOT what happened in my case.
My printer (HP OfficeJet Pro 6970) does NOT auto-upgrade, and it was
indisputably working fine until the `ghostscript' "upgrade" mentioned in
the bug report.  I was doing printing all day yesterday (in colour) and
everything worked fine until after that upgrade.  Also, asking the printer
to generate reports (either on the front panel or via HPLIP from Linux)
works fine, as does copying.  Its very probably only stuff from Linux/CUPS
which goes wrong.  (Having said that, I haven't tried "raw" PostScript, but
I also don't want to waste any more blue ink.
cheers!
    -blf-

On Fri, 22 Feb 2019 at 18:05, Matthew Covington <email address hidden> wrote:
> I started having the same problem today on an Ubuntu 16.04 machine and
> an HP OfficeJet Pro 6978. However, I haven't updated ghostscript (or
> anything else recently). I was wondering whether it was an HP update
> that broke the printing. My printer is automatically installing HP
> updates.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1817308
>
> Title:
>   GhostScript Update causes Blue Background
>
> Status in ghostscript package in Ubuntu:
>   Incomplete
>
> Bug description:
>   I am running 64 bit Linux Mint 19.1, the Cinnamon desktop 4.0.9, with
>   kernel 4.15.0-45-generic.
>
>   Two days ago an update to ghostscript dated 20 FEB 2019 appeared, and
>   was applied to two of my machines (One is an Intel and one is an AMD,
>   but both are kept fully updated) that share a networked HP OfficeJet
>   6700 Printer.
>
>   At some point following the update, I happened to print a document,
>   and ended up with a blue background on every page, even otherwise
>   blank second sides. This occured regardless of a variety of
>   originating applications I used, such as LibreOffice, various text
>   editors, and even the CUPS "print test page" option.
>
>   It took me a while to troubleshoot this on that first machine (trying
>   different apps, reinstalling CUPS and so forth) until I realized the
>   new ghostscript update was the issue and that (after trying to print
>   from the second machine) it was affecting both machines.
>
>   I should note that, using the "non-CUPS" appearance of the same
>   printer, no blue background is present, but of course this provides no
>   features like ink-level reporting, dual-sided printing, etc.
>
>   I "restored" the ghostscript stuff from the last Timeshift backup and
>   that cured the issue but I think this is a serious matter that should
>   be addressed immediately (not the least because it's hard to read
>   black text on a blue background and it wastes a lot of ink).
>
>   I first posted this at
>   <https://forums.linuxmint.com/viewtopic.php?f=47&t=288613#p1598888>
>   and then sent an e-mail to <email address hidden> (whose name was
>   on the update information) who advised me to post this bug here.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/ghostscript/+bug/1817308/+subscriptions

-- 
“How many surrealists does it take to    |  Brian Foster
 change a lightbulb?  Three.  One calms  |  somewhere in south of France
 the warthog, and two fill the bathtub   |
 with brightly-coloured machine tools.”  |