Check the plastic quick release coupling where it leaves the fuel sender they are prone to cracking their threads due to a thin wall thickness, it’s known as a CPC coupling.
BMW don’t sell new ones but Motorworks in Holmfirth UK do if you need one. Personally I would recommend you pay a little bit more and replace the OE plastic version with a metal one.
You will probably see petrol puddling in the front of the fuel sender well.