Gil--I'm not sure what a bulk universe assignment is (?). I can't send a screen shot right now, but my setup is that I have the first universe setup as a COM1/LOR universe blocked out for AC (LOR) channels, then I have E1.31 universes setup from universe 2 thru 15, all set as multicast with the last channel 510 on each universe since I am using an E682....
The first night I noticed the problem, I had not yet hooked up a controller. Once I rendered, xlights was happy. However, now that I have hooked up one of my controllers, I am physically seeing the problem on the lights but the displays in xlights/NC are correct. Fortunately, on the "fireflies" sequence, I am applying NC effects to the megatrees at different times, so it is really obvious that my megatree5m is receiving my megatree3m data stream for some reason.
As I noted last night, when I send universe/channel on/off signals from SACNView software through my controller to my lights, everything works correctly (e.g. when I tell it to turn on universe 7 channel 1, the first three LEDs light up red on the first strip, etc), so my controller is setup correctly. I am telling xlights and my controller to start my megatree5m model at universe 7, so the two should be synched up in that ballpark.
I will keep troubleshooting when I get home tonight.
Thanks for your help!!!!!