Updating to 2.3.3 broke my build.
Usage in code:
const ReactGA = require('react-ga');
...
ReactGA.initialize(GAtoken);
Downgraded to 2.2 and it worked.
Also experiencing the same issue.
I am seeing the same issue, went back to 2.2 and everything is fine again.
The issue is discussed at length here: https://github.com/react-ga/react-ga/issues/165
Thanks for the reference @mandy6720