The library is deprecated by its author, see below comments bu author:
“This repository has been archived by the owner. It is now read-only. Deprecated. This is a very old polyfill which served old browser decently for the last 4+ years. I am not actively maintaining this project but I would eventually accept PRs if you really need to use it. Please have a look at better alternatives such ES-Shims.”
There is a known issue with infinite recursion in this library that’s been identified in a pull request opened a year ago that the author has not yet reviewed or merged.
https://github.com/WebReflection/es6-collections/pull/45/files
Magento should update this library as it causes issues with third part JS conflicts.