I use only analogue input right now and Digital AES output.. Yes I did notice the light is flashing even when I had no cables at all inserted to the H8000fw but also when Inserted a digital AES cable I the EXT is still flashing.I tried wordclock I did also remove the Wordclock cable and did try to use Eventides internal clock and use my RME as slave clock, still EXT flashing and still unlocked as it seem.
in the video I demonstrate when I use wordclock, that they are in sync, as you can see in the video I change clock speed on my computer and it change in the Eventide. I switch between 96 and 44khz .
http://delafil.se/key=f39de1e1f86d4b8b3e995863e5f81f29&lang=en
I use the best cables available mogami multi core cables.
http://www.frontendaudio.com/Mogami-Gold-AES-Snake-p/9999-06900.htm
My eventide is always OFF when connect new cables.
I use version 5.5 of the H8000FW, it says that you no longer need to "enable" word clock" in setup, in fact the "word clock" enable option has been removed from the "misc" menu in setup as it seem.
Some pictures of my setup might make it easier for you to understand since you said it would be easier if you was here.
