Not Permitted Users Receive Notification from Team Calendar

Summary

Confluence users that had previous subscribed to a calendar still receive notifications when calendar have new events added or when events in the subscribed calendar are modified even after their 'can use' permission has been revoked from the Confluence.

Steps to Reproduce

1. Create a new user in Confluence.
2. Assign a group that are allow to use/login to Confluence (eg. confluence-users) to the user
3. Make the new user watch a calendar in Team Calendar
4. Remove the group membership from the user. The user can no longer use the Confluence.
5. # Modified or add a new event into the watched calendar

Expected Results

Confluence should not send notification to users who are not permitted to use the Confluence

Actual Results

Confluence process the notification and publish notification to non permitted user.