Why aren't notifications from within a card comment sent to recipient?

[Nick Savage]

When I create a comment in a card addressed to a teammate he receives an email notification

When that recipient replies with a comment to myself I get no notification email

[Michael Pryor]

Does the reply include your username?

You could also "Watch" the board and then you will get a notification whether they include your username or not.  

Also have you checked your notification settings to see if they are set to send you an email daily or immediately?