Losing input on new audio track

I’ve got a weird problem with 1 of my projects. It’s nothing special, a few recordings to mono audio channels and 2 midi tracks (1 to halion and 1 to my drummodule) and all of this works just fine.

The problem is that whenever I add a new audio track my entire audio input is lost. As long as I don’t add a new audio track I can do whatever I want, I can still record audio into the existing audio tracks and in the transport bar I see the audio input meters move.
As soon as I add a new audio track this will no longer work. None of the tracks I can record to, and the input meters in the transport bar will dissappear. Selecting the right inputs on the audiotrack doesn’t make any difference at all. On my soundcard I can see the signal leds light up so that’s all fine.
All other projects work fine, and if I close this specific project and open it again (without saving obviously) it’ll work again untill I add a new audiotrack.

Any clue on what this might be?
Cubase Essential 5 32 on W764.

reboot fixed it, weird :confused: