apt-get update ending in Problem executing scripts APT::Update::Post-Invoke-Success

Hello, I have recently added node sources to my Ubuntu 14.04 droplet (the LEMP package) and today when trying to run apt-get update I’m getting following error message:

...
Ign http://apt.newrelic.com newrelic/non-free Translation-en
Get:5 https://deb.nodesource.com trusty/main Translation-en_US
Hit http://security.ubuntu.com trusty-security/universe Translation-en
Ign https://deb.nodesource.com trusty/main Translation-en_US
Ign https://deb.nodesource.com trusty/main Translation-en
Fetched 6,413 B in 4s (1,566 B/s)
Killed
E: Problem executing scripts APT::Update::Post-Invoke-Success 'test -x /usr/bin/apt-show-versions || exit 0 ; apt-show-versions -i'
E: Sub-process returned an error code

The package list seems to be read but at the end there’s this error. The only sensible solution I found googling is to remove apt-show-versions package if I don’t use it. I haven’t done that yet, hoping I would find another solution.

Thanks in advance.