Once I open a project in Cubase 8.5, and before I start playing anything, I can see audio activity on my input channels. If I go to the VST Connection window and disconnect my Audio Interface, the signal disappears. Reconnect and it comes back. I have two workstations with Cubase 8.5. I use UR44 with one and Komplete Audio 6 with the other, and the issue is on both work stations. If I close 8.5 and open Cubase 8. there’s no problem. So it’s not a problem of my audio interfaces. It is definitely a Cubase 8.5 problem.
There is also the appearance of signal on the outputs. But on the inputs it’s dynamic - the signal is moving. On the outputs it appears to be static. Very low and no movement. But the green coloured signal is there.
I have recorded this signal and normalized it. It’s noise. Not from my PCs either. Remember with the same audio interfaces and Cubase 8 it doesn’t happen, only with 8.5. Will report other issues as/if I find them.