I would like to report about open-redirect on hackerone.com
Here is the PoC that redirects to example.com IP address: https://hackerone.com/%2F1572395042
There is one more strange behavior in URL. For example: https://hackerone.com//hackerone.com - works https://hackerone.com//hackerone1.com - doesn't work
I will investigate it further and get back with details if I find something more.