Failed to parse SourceMap with accounts-ui(-unstyled)

I was planning to tweak accounts-ui package a little bit, so I removed accounts-ui and added accounts-ui-unstyled separately. After this, I started getting this error in my console when I’m running my app which uses accounts-facebook, accounts-google, and accounts-twitter:

Failed to parse SourceMap:
http://localhost:3000/packages/XXXXX.map

The error persists even when if I checkout to my previous commit, or remove accounts-ui-unstyled and add accounts-ui.

The app works, but very slowly, and authentication takes years. I’m getting this error on Chrome, but even on Firefox, Still the authentication barely works.

Any help will be appreciated,
Thanks,