Water in Battery Compartment

Hi everyone! I bought a used 2009 Challenger SE a couple years ago. Early this year after we had a ton of snow, it would keep running after I took the key out of the ignition and/or wouldn’t start. The dealership found the battery compartment was full of water and that obviously was causing electrical issues. They swore they couldn’t find the leak, ran all the tests and couldn’t replicate the issue.

We’ve had a ton of rain recently and the car is now doing the same thing. Popped the trunk and the carpet is soaked, so the water’s getting to the battery through the inside of the trunk I think. Anyone have any suggestions on which seals to look at first to find the leak?