Reply to in bbpress doesn't work for new topics, only for replies

[smith89er]

Thank you so much for this amazing plugin! I am experiencing one strange condition: If I subscribe to a topic, I can use the answer by mail function without any issues. When I create a new topic, I get the message that I can't reply to this topic by mail, no code-mail-address is listes as "reply to". When adding a post to the new topic (after subscribing to the topic) I can reply by mail to that notification. Is this intended and is there any way to change it?
WP 4.8, reply by mail current 1.0rc4 I think, bbpress, Buddypress and Buddypress group mail installed and up to date. Using Sparkpost as mail system.
Thank you for your help!
Patrick