I'm confused by this, though it sounds like a bug exists I'm not sure I understand it.
Alice and Bob example...
Alice creates a conversation, auto-follows it and sees the "email notification" box checked.
Bob replies to conversation.
Alice doesn't receive a notification.
Also, I've just checked the last "PM" i sent / started to 6pt and the "notify me by email" box is unticked. It's ticked for all the conversations someone has sent to me first.
I'm confused by this, though it sounds like a bug exists I'm not sure I understand it.
Alice and Bob example...
Alice creates a conversation, auto-follows it and sees the "email notification" box checked.
Bob replies to conversation.
Alice doesn't receive a notification.
Is that the scenario?