Issue security levels
The Advanced Portal Reports for Jira Service Management does not currently show issues in the report that have Issue security level set in Jira.
This means that if you have set restrictions to tickets using the Issue security levels in Jira, the Advanced Portal Reports will not display those tickets in the report, even if the user should have access to them.
In general, issue security levels were introduced in Jira, long before Jira Service Management was created. Their idea is to restrict issues for the Jira users and trying to use them in the JSM portal to restrict standard customers is not their intended purpose. Similar effect can be achieved by not setting Customer Request Type for those issues that should not appear on the JSM Portal.
Possible workaround
You can add the atlassian-addons-project-access group (https://confluence.atlassian.com/servicedeskcloud/blog/2017/02/add-on-permissions-update) to the security level settings in order to show tickets with security levels set. This option will allow our report to show requests to the customers based on their permissions and the Advanced Portal Reports configuration even if you use issue security levels. However, the actual values of the issue security levels will be ignored.
If you are using Issue security levels, and you would like more information about our proposed workaround, please raise a ticket in our Support center and we will investigate together your exact case.