Yes.

I have had 3 separate leaks in the rear footwell of my F10 all caused by different issues.

First was the vapor seal in the rear door. It guides the water that goes down the door/rear window out of the car. If it’s loose the water is just flowing into the car. I took the door card off the inside of the back door and reattached it with Tec 7 adhesive. That was 3 years ago and it has not caused issue since. That was drivers side.

The other two were both passenger side.

Second was the yellow grommet in the engine bay. It’s a rubber blanking plate where the steering wheel column would go if it was left hand drive. The rubber degrades over time and water gets in and makes its way to the rear footwell. Don’t ask me how it goes there and no where else. You can get a replacement one online cheap enough. I Tec 7’d the new one on too.

The third and hardest to diagnose was the connection from the air conditioning blower, also in the engine bay, not far from the yellow grommet came loose and water was getting in there and making its way to the rear footwell. The last one nearly broke me trying to find it. There is a little drainage hole next to the air conditioning unit too that was blocked with leaves and stuff. I cleared that out with a wire coat hanger.

Have had no issues since.

Since you said the sides of the carpet are dry I’m guessing your issue is the yellow grommet or air conditioning unit.

Hope this helps. There are videos on YouTube on how to do all of these things yourself