Hi @Marco_Polo, I'm just looking into this now. I download the latest release from here:
I then create a new project. I add a CsoundUnity component, edit and add the Basic.csd script to play back some sinewaves with panning:
a1 oscili 1, 400
a2 oscili .5, 1
outs a1*(a2+.5), a1*(1-(a2+.5))
Start my scene and I get panning. No high pitched craziness, just good old school sine waves. I fail to recreate your issue here with the high pitched sounds, but I do note that panning in Unity doesn't work, although the stereo image is coming from Csound just fine. A quick search of the issue shows that there is a long standing bug in Unity that causes this problem. The guys at Heavy also have the problem:
Also check here:
What I can do is programmatically retrieve the pan position and use it to alter the gain of the left and right channels. I'll try it out and see how it works, although I'm afraid we may get some artifacts in the audio when the panning is changed. I'll try it out and let you know. Unity really should look after this itself.