Hi Ivan,
Thanks for getting in touch with us.
It seems like your Authentication Server Logout Endpoint setting is missing in the plugin configurations, this is the reason when the user is trying to log out from JIRA, the user session still exists in Gluu Server and the user gets logged in again.
To avoid this behavior you can simply configure Logout Endpoint in the plugin. With this, you will get logged out from JIRA as well as Gluu Server on logout request.
Please contact your Gluu Server team for Logout Endpoint.
Let me know if this helps.
Thanks,
Shradha