Karma Uncaught RangeError: Maximum call stack size exceeded

I'm getting this error from Karma when trying to run grunt karma:debug:

11 11 2017 00:00:00.000:INFO [Chrome 62.0.3202 (Linux 0.0.0)]: Connected on socket /#AAAA-AAAAAAAAAAAAAAA with id 99999999
Chrome 61.0.0000 (Linux 0.0.0) ERROR
  Uncaught RangeError: Maximum call stack size exceeded
  at http://localhost:9876/context.html
Chrome 61.0.0000 (Linux 0.0.0) ERROR
  Uncaught RangeError: Maximum call stack size exceeded
  at http://localhost:9876/context.html
Chrome 61.0.0000 (Linux 0.0.0): Executed 0 of 0 ERROR (1.035 secs / 0 secs)

What can be the cause? it started to happen overnight after a commit with some big JSON files. If I go back to the commit without the JSON files, the command starts working again.