xlights 2018.47 not sure about earlier but I was having an issue testing my Arches - RGB model. In the layout 10 arches each arch has it's own start channel. universe 64-73 channel 1 - 504 ea. The layout is correct starting (30245) but in the testing models test screen, my model Arches - RGB start channel is double and doesn't send out any data (60490). The output tab does show the correct start channel @ 30245 Here is a pic of it.