Using the current Jira version integrated with Crowd, if a change is made in Crowd's user repository (Internal Directories or LDAP servers instegrated to it), Jira will be able to see that modification only if the Crowd Client cache times out or if Jira is restarted.

A Refresh Cache button would be useful and would allow Jira to see the updates in the repository faster (and without restarts, when a quick update is needed).