CasperJS engine_scripts error when using absolute paths

Hi!

I tried to run CasperJS, where my config has this line:
> "engine_scripts": "/home/node/app/templates/casper_scripts",

However, when trying to run it, I get this error:
> CasperJS: CasperError: Can't find module /home/node/app//home/node/app/templates/casper_scripts/onBefore.js

Using a relative path (so, "templates/casper_scripts") works fine.

Did anyone else encounter this?

Env. info:
- BackstopJS v3.5.2
- OS: Docker, FROM node:10.7.0
- phantomjs-prebuilt 2.1.16