Hi Ben,
This is a strange issue because it seems that badge was earned a month before on March(http://take.ms/Z2u9t) long before the user was registered with no stream/activity record as well. I'm not sure why this happens. I have tried registering as a new user and created some story posts but it seems I could not replicate the issue.
If you want, you can delete the badge from the user here(http://take.ms/XmusF) and keep an eye out on this issue so that you can let us know if it happens again with more details on how to replicate it.

Hi Raymond, thank you for your reply. I will keep an eye on this but it sounds like something that won't happen again.

Understood Ben. If you can no longer replicate this for some time, you can mark this resolved. If you have any issues in the future, feel free to start a new thread so we can look into it.