That filter media looks like it's holding a lot of carbon for that relative low milage. Not familiar with this engine but it looks like it gives the oil a hard time.
Can you mesure how hot the filter gets at op. temperature and after shut down?
I can track oil temps via the SRT dashboard, it has a very large coolant/oil heat exchanger, so it doesn't get super hot, max is probably around 120C.
But yes, the 6.4L isn't super kind on oil. High compression, huge bores, mostly hemispherical chamber, which runs pretty dirty at low speeds. The oil is always jet black when changed (find my previous OCI thread on here, you can see the oil) but this is an extended drain Euro oil with multiple OE approvals, it should be able to handle this interval without anything plating-out.
The filter still has some oil in the media, it's the nature of the multiple layers of synthetic media, you'll never get it dry, so what you are mostly seeing is black oil, not carbon IMHO.