Hi Patrik,

I am sorry for the delay of this reply.

Regarding your issue, do you mean those event stream with the title of ' xxx is going to the event yyy' ? Please see http://screencast.com/t/zyuEe6ShD
If yes, then by right the event migrator will pick the member join date from db table column #__community_events_members.created. Anyway, I've checked your JomSocial one of the event 'Thai Traditional Massage & Spa.' and apparently the member join date of this event is empty. Please http://screencast.com/t/4J0t92wcpZBC

Can you pass me your FTP account and your MySQL phpMyAdmin access so that I can help you to patch these stream date?
Please advise.