Cabin leak

[Bonymaenjack]

I've removed my carpet after replacing the heater matrix last winter, brand new ( Nissens ) and whilst cleaning up the floor and replacing some frayed wiring harness tape I noticed a small wet patch directly beneath the join of the plastic cover where clip 3 9in the image ) engages, this isn't a regular occurrence , I don't believe it the matrix and if it isn't then could rain water enter the cabin via the heater . I also have rain water entering at the corner frame edge where it builds up on the sill then overflows into the car ( brand new "OEM" Chinese made door frame seals )
https://www.realoem.com/bmw/enUS/showpa ... Id=64_0514

[Bonymaenjack]

Bump , anyone?