Most likely you have a moon roof rainwater drain clog. The subject is well covered in these threads.
Also check your trunk/spare tire area for water. If your electronics have not been moved, you could have problems due to water damaging the electronic modules located there.
This subject is also covered in these threads.
BMW tech here,,,if you are talking about the front passengers floor area,,,,it could be the sunroof water drain or the front passengers door panel vapor barrier could be leaking,,,,,my blog page bmwtechnician
There are scuttle drains under the cabin filters . One is under the ebox and the other is just under the master cylinder . If they get clogged with leaves and dirt . The compartment fills with water and drains in the floor boards ...
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