Problem editing moderators for a series of sessions

When editing a series of sessions (sessions that have been scheduled using the repeat feature) to add a moderator, the added moderator will then not be able to join the session.

The clarify, the exact series of steps to replicate this bug are as follows:

1. Schedule a series of sessions using the “Repeat” feature.
2. At a later date return to the series and from he context menu for any of the sessions select “Edit series”
3. Add a user as moderator in the Roles and Access section and submit the change.
4. Attempt to join any of the sessions in the series as the added user.
5. Error will be displayed “Failed to launch session”.