Anyone familiar with this A/C noise?

Hi,

When I use the A/C on my Superb iV (electric AC compressor), I hear this weird backround noise attached.

(sound is more present in recording around 30-40s and until the end)

It is not very loud, sounds like someone sending morse code using an electronic synthesizer - for lack of a better description...

Also somewhat covered by the normal air noise, but once you hear it it's quite obvious.

A few other details:

- it usually does not appear straight away, needs to get the A/C compressor running and in a state of temperature regulation

- it will occasionally go away but then will come back

- there is no correlation with blower fan speed or flap position

- I have done a A/C flap calibration via OBD2 and this doesn't change anything

Anyone have heard this noise before and know what it is / how to resolve it? Or just normal?

Cheers