Hi , 2017 a6 with the same leak on both sides of the car , running down A frame and into foot well .
The water as I'm sure is the same for most gets in where the water flow / level becomes to much for the drain and builds up ( doesn't take much ) it overflows to the inside of the wind defector and the leak gets in where there is a steel spring finger . Water gets in where it locates towards the front .... BUT regardless of that , iv found at the rear of the spring finger , under hole is a 10mm × 10mm square hole in the frame on both sides which flows directly in onto the headliner.
Joke of a design.
I'm working on a fix at the minute 🤞
