ActivityTimeline administrator can control the way the issue appears on timeline panel, fully or partially synchronize all recent updates from JIRA, remove issues manually from ActivityTimeline cache.
The Issue appearance and Issue Card appearance can be customized on Configuration > Issue Appearance and on Configuration > Issue Card Appearance pages.
In order to run data synchronization or add CSS styles to issue appearance, from AT Dashboard go to Configuration > Synchronize tab:
For more information please refer to the following pages: