Ventilation still stinks when it rains

Who of you has the problem when it rained, that after the departure it stinks out of the ventilation for a time modrig/muffled? (climate off) I’ve actually had the problem since always…. Also my spring cleaning did not help…. All dirt under the cover removed. A drain freed (all 4 drains are free). Before I tried it once with activated carbon filter but did not do anything. My guess is that the rain from the windshield runs under the bar of the windshield on the filter (set red circled on the picture). I don’t have such a sealing impression. Had it taken off to clean the disc there too sometimes. Wouldn’t it be possible? I was sure but somewhere I had read exactly of this problem that it runs on the filter there.