Extra Data in Sub-Report

I have a report that, based on a query, finds names in an affiliate (city) and displays their information in the header of each report. The detail then contains a subreport that runs another query based on the persons "role" and finds other people that have the same role (so in other words, it prints multiple people per page in the detail section, all with the same role). When I preview the report, the subreport will randomly display other roles from other people. The numbers don't match, the two reports are linked through child and master fields and the query even has a WHERE clause that checks to be sure that the two roles match. It doesn't seem to matter how many roles actually match, it seems completely random but occurs for the same people each time.