Created a KSC report with some random graphs in Meridian 2016.1.4 with the "Override Graph Timespan" option. Viewing the report works with no problems. If I use the "Override Graph Timespan" dropdown and choose "Last Week" or "This week", a wrong timespan was calculated (end time before start time) and the graphs can not be displayed. Please see the attached screenshot, captured on May 8th with the option "This week" and the calculated graph time spans from May 14th until May 13th.
This behavior could not be seen on a Horizon 18.0.1, where the "This week" timespan was calculated correctly.