Headset with interferences while calling

Hi all,

now I also own a Meizu M8. I like it.
But I don't like the interferences I hear over the Meizu headset while I am calling. If I only use the headset for listening, there are no interferences, only when I am calling. The odd thing is, that there are no interferences if I use the Recorder-App with my headset -- maybe only the mic is activated?

I don't think that it is some external source what causes the interferences, because I tried it in every room with no difference.

Is the Meizu headset poorly screened?
Does anyone has the same issue?