Confluence cloud team calendar gives "No users found" message

[Warren]

This applies to Confluence cloud team calendars.

I have 2 users who have been using Jira and Confluence for months. Suddenly today, they are not showing as users in the team calendar. The Who user picker box gives the message shown below if they themselves put their name in or if anyone else does. @ mentioning in both Jira and Confluence still work, it is just in the team calendars that this is an issue. I'm the site Admin and as far as I'm aware, nothing has changed internally to affect this.

Any help or advice greatly appreciated.

[Warren · Accepted solution]

This has been resolved by Atlassian performing a content index on our Confluence site.