This bug can be reproduced on online demo as well. Here are the steps: 1. Open online demo here: http://www.daypilot.org/demo/Scheduler/ImageExport.aspx 2. Move the two events on day 26 in Room B to Room A and then click on Export button.
It's now fixed in build 6.5.2301.
See also: http://www.daypilot.org/daypilot-pro-6-5.html
Thanks for reporting the issue!