Hi,
It could be the start of a reasonably common fault in the early mk7’s. Had two replaced in my old mk7 GTI and one replaced in the mrs old GTD.
Only ever happened when it was cold. VW couldn’t fault it when it went in much to our annoyance.... despite me informing them it only happened in sub zero temps. Ended up filming it and emailing them the video to prove fault.
Not sure if yours is still under warranty but if it is film it and they will replace it.