CVT transmission makes strange noises

Good day I have a problem for a long time, but the workshop can’t/will help me. Workshop Reason: We don’t know if the noise is normal, and since we don’t have a comparison vehicle, we can’t test it. Ok … what then defied me, I noticed that they had a comparison car a short time ago. But I noticed it too late and it was already sold. I hope you can listen to the file I uploaded. Sorry about the agony. i… but as one hears a very strange sound comes about when I give up while rolling (very) lightly and let go again.(so to say only briefly tap) Comes sometimes in the traffic jam before … or in the traffic calmed Berreich. Have a Lancer 2008 with CVT transmission 143 HP. Please for help ! Ps.: I had my cell phone fixed in the engine room … therefore one hears the engine so “loud”. But this “knarches” can also be heard in the interior.