Email Subscription not honoring private replies?

I noticed this while being subscribed to a thread on the Easy Digital Downloads support forums.

I was subscribed to a topic. I posted a private reply, and then another user posted a private reply:
https://easydigitaldownloads.com/support/topic/updates-not-seeing-the-1-4-release/#post-35853

Since I was subscribed to the topic via email, I received a notification but this notification contained the contents of their reply. In this case, his license key.

If you want to see the information from my email contact me and I can provide.

https://www.ads-software.com/extend/plugins/bbpress-private-replies/