BackstopJS halting but nothing is appearing in the command line

I'm currently running some tests on a work project, and I appear to have hit a bit of an issue. when running the backstop with puppeteer and with `"debugWindow": false` it seems to get so far through my scenarios and then decide its going to do nothing else.

It doesn't crash in fact it took me a while to realise it had stopped as it was just sitting on the last step for a scenario and looked like it was just waiting for the next scenario to start. I've tried setting `"debug": true` but I don't appear to get any debugging output into the console.

What makes this problem even stranger is if I set `"debugWindow": true`, everything works fine (albeit the browser does take control of my machine for a while)

This is running on a rather large project and has somewhere in the region of 500 scenarios to work through. I have had it running on a project with around 215 scenarios and it works just fine.

Is there any way to get the command line output to be more verbose so that I can try and pinpoint the issue?

Thanks