[Freeswitch-users] Noise on line, does not show up in recordings

Hi all, I frequently get noise during calls with my FreeSWITCH deployment. It sounds like a brief burst of distortion - typically less than a second. I've had it happen both when using playback with WAV (different formats - I found recommendations suggesting 8000Hz, 128 kb/s mono and it shows up with that format as well) and text-to-speech with flite. It happens at unpredictable moments - it's not the same from one call to the next. I've added a record_session statement to investigate in more detail, but the noise does not show up in the recording. Does anyone have advice on what might be causing this or how I could further debug this? Kind regards, Sam