There is an issue with the Domain Mapping in emails generated by Subscribe by email.
The mapped domain is not being shown in all cases. Sometimes it reverts to the unmapped domain.
When I "Schedule" a post to be published, the email goes out with the mapped domain.
When I "Publish" a post directly, the email goes out with the unmapped domain.
Here's a screenshot: http://www.screencast.com/t/QJUKNPjT
Here are out network settings for domain mapping: http://www.screencast.com/t/5l3e4eqoNo
I posted a previous ticket on this but got no response from the Subscribe by Email folks, so now I'm trying this approach. Here's a link to the previous ticket: https://premium.wpmudev.org/forums/topic/subscribe-by-email-domain-mapping-issue#post-280895