Hello John.
Just to clear things up before the support team gets in contact.
Did you monitor your artnet with something like http://www.lightjams.com/artnetominator/ on your capture computer?
Regards
Alexander
Hi John,
I believe ETC have chosen to output Art-Net at a lower refresh rate from the offline editors in order to prevent live shows from being run with it. That would be consistent with your description as well. The best way to find out would be to check with ETC support.