This post seems to be related to https://community.etcconnect.com/etc_beta_sites/f/149/t/15537.
I have range patched 1000 RGB Fixtures starting at 1/1 and the fixtures bridge across universe bounds. I have EDMX disabled and has tried patching in both output and port/offset views. In this scenario fixture 171 always ends up with address 1/511 - 1 and fixture 172 begins at 2/2 and so on.
EOS Ti - 2.3.3.9.0.10