Email sent twice in activity to same person?

Hi,

I have a General activity in workflow and in there i have a default client event and also a send email event.

The send email event sends to a specific email address, but it is sending the email twice... Any reason why?

In my destination rule i have it set to:

All at once

Specify slots 1

Resolve all role and groups to users

Destination Set:

Ad.User.getusersbygrooup.name -> my AD Group

My AD Group has two users in it, is that the reason why it's looping through the activity and there sending the EMAIL event twice as well (based on number of users)

If it is, is there any way round this? Or would i need to move the Send Email out of that Activity all together?

Thanks