Good afternoon,
Land Rover has not figured out (or even tried) to fix their troubled sunroof drain tubes. Every LR/RR I have owned has had failed tubes. All were broken right at the top.
I have seen various posts about failed audio amps. Well, mine failed also. It was due to the failed sunroof drain tube. Yep, both sides broken right at the top. Tube fine, but fitting was no better than a soup-sandwich.
The water is very easily draining down the pillars to the frame itself. It takes a while to actually get noticeable moisture in carpet. Headliner gets wet of course but dries quickly. Not so the standing water in frame. When enough water has accumulated and your carpet is wet, TO LATE!! Your audio amp is bolted under the driver's seat to the lowest part of the body. It survives bathed in water for bit but eventually you get the crackling and static from every audio input. Another indication is explained fogging or moisture inside the windshield after a period of sitting locked.
Fortunately, the fix to the drain tube fitting is fairly cheap and easily done by your competent body shop.
Unfortunately, the amp will cost about $1,300 (1200 watt) and cost of dealer to install and register with the vehicle.
Since Land Rover has ignored the age-old problem of their sunroof drain tubes for literally decades, there is no reason they shouldn't issue a fleet wide recall and fix it. As I said the fix is simple. Be even better if they replaced the audio amps destroyed by the water.

 

It is a shame that they do not admit this or at least recommend that drain lines be checked and cleared at every service interval. This problem is not just limited to Land Rover, as a slew of other manufacturers have the exact same issue with even more devastating results. On Volvo's the drain can cause the whole electrical system to malfunction requiring all new electrical wiring at a cost of $10k plus.