@user-name doesn't fonction in a newly created circle

How is it now?

After a starting a discussion in a Circle, I've decided to create a new one for clarity reasons.

I've created the new circle and added all the users at once. To ping a user about the new palce for a discussion I've tried to mention him by @user-name. But even if all the members are register in the newly created circle (I see them in UI and in the Django Admin) I cannot ping him. The only user I'm able to ping is myself.

How should it be?

When a user is a member of a circle we can ping it with @user-name and he should see a notification.

Steps to reproduce

1. Create a circle
2. In circle admin add all the members even if the UI Doesn't update
3. reload the page (F5) to see all the users in the cicle admin page
4. Try to ping with @user-name a newly added member of the Circle