violetpow:

Terminator is on the H8000 WC out.

Assuming that the RME is the WC source, you need to have the terminator on the H8000 WC in. If you indeed meant "out", this may be the cause of your problem.

violetpow:

ADAT status is "slipping"

You don't say where the ADAT comes from and from where it gets its clock. This again may be the source of the problem.

violetpow:

I expect that the wordclock is synced

If the Wordclock is unlocked, the "Source:" line will flash.

violetpow:

if i pull now the WC cable out and back in, the ADAT is not slipping

This suggests that the ADAT is the problem, not the wordclock. Check that the ADAT is properly clocked (as above). Also, try a different ADAT cable – the ADAT sockets on the back are a bit tight, and if the wrong cable is used, or it is not pushed in hard enough, you can get an unreliable connection.