this was the same problem I was seeing using the Martin Ether2DMX boxes for the special olympics, and it was the same problem on Rush. When you would do a fast bump.change, the previous state would stay for about 5 seconds.

We changed to Virtuoso Node 2s (artnet) and the problem went away. On Rush they changed to the Artistic Licence boxes (I think) to solve the problem.

Richard, maybe it would be good if you put up a page somewhere with known problem boxes and successfully used ones, to help people out in speccing the right gear..