Report data only showing when List access is ALL

Version 7.11.3
Sugar Version 6.5.25 (Build 344)

I have a role created which has access to all functionality, but only for the data within their GROUP. Everything works well: viewing Leads, viewing meetings etc., they can only see data for their security group.

When it comes to reporting, things get strange. It’s possible for someone in this role to run a report on just meeting data, or just lead data and it works fine. But if we add in criteria to display lead data associated with a meeting, then nothing will display. The only way to get it to work is to set Lead List value to ALL instead of GROUP for this role. This causes me a problem in all other areas of Suite though, so is not a solution for us.

I’m wondering if there’s something I’m missing here, or a way for role to run a report showing joined Meeting/Lead data without having full access to all lead data outside of their group.