Travis build fails due to core-js, but local builds (multple machines/OSs) work fine

My project’s builds started failing with the following error:

[ERROR] error An unexpected error occurred: “/home/travis/build/mcpierce/comixed/comixed-frontend/node_modules/core-js: Cannot read property ‘config’ of undefined”.

I rolled back the commit that first showed this failure, force pushed the branch but the error remains.

I’m at a loss as to why this is occurring. I can build the entire project on multiple machines running Windows, Linux and Mac OSX without problems. But ever reverting things so the code is what was build on the last successful build still fails and with the exact same error.

What can I do to fix this? It’s got me mystified since it doesn’t seem to be related to the project’s code but to something in the build environment.