Intrument Track Routing Bug?

I’m using Cubase Artist 8.0.35 on a PC, Win. 7. A friend of mine using Artist 8.5 has had the same problem but just once after rebooting following a power outage.

This is not a VST connections issue. I’ve experienced this 3 times in 3 different projects. I will open a recent project and get no sound from one or more instrument tracks even though a loaded instrument still appears in the inspector as does the routing input and output info in the inspector. When I go to the inspector output for the instrument track, choose no output and then re-choose the same output as before, still no sound.

But when I open the Mixer window, there is no output for the track that’s listed even though there is in the inspector. As soon as I select an output (stereo bus) in the mixer window I get sound from the track again.

I cannot reproduce this at will.