Missing Contact information in Side Conversation

Hello, 

When I forward a Message with a Side-Conversation, the person receiving the message (outside Zendesk) does not see the initial e-mail address of the message we forwarded. 

See Picture. The yellow marked place, should be the end-user e-mail address instead of the end-user name. 

Is there any setting to be possible to change this? It should be normal, as in every mail when you forward this, that you forward also the initial informations.