To reproduce this bug I used this repository project https://github.com/intercom/example-single-page-app-install which contains bare minimum - react router & intercom. Follow the instructions to set it up in repository description.
Steps to reproduce:
- Open the project on new tab/page (without any navigation history)
- Click on About and then on Home links
- Open up the intercom and wait till it loads it's contents
- Go back in navigation history 2 times
- Go forth in navigation history 2 times
- Intercom breaks / becomes unresponsive and transparent
There may be more ways of reproducing this bug, but this is the most consistent that I found.