This issue was first posted on Oct 15, 2015 by Mike Velardo, titled BOXI Report - Multiple Lines, but instead adding to that post, I thought it was better to start a new post.
I was having the same issue as Mike so I tried several of the suggested solutions but none of them worked. We are at a point now where we need to find a resolution to this multiple line issue.
I have a report that's in a horizontal table, joining the cr.req and act.log tables in the filter section of the report: Call Req Id equal to Act.log Persistent Id, the date range is previous month, there are two variables that pull data in from the activity log, eg. if Type = "TR" then 1 and if Match([Action Desc]; "AHD63013:sla expired*") then 1 and those don't show the duplicate lines, but when I add a 3rd variable for If Match([Action Desc]; "*'Closed' to 'Open'") Then 1 that's when the report shows the duplicate lines.
Any help would be appreciated.