There are a few threads here and there about wet A-pillar top corners. There are many contributing factors, and poorly designed roof is one of them.
Here is what the mount of the roof bar looks like:



Note, there are at least two issues with the design:

1. The mount of the roof bar is indented, it has a hole that goes down, so the water is invited in. A better design would have an outdented mount that acts as a barrier that water would have to cross.

2. The is a hole within the hole where the arrow is pointing. If you put a wire there, you will see the end of the wire come out inside of the truck.

Therefore, no matter how much you tighten the roof bar nut (and it is only 24lb/ft as per RAVE), there is a chance of water getting in. The long-term solution is to put a lot of silicone around the base of the bolt that goes in:

 

Another issue is nobody ever gets a ladder and cleans the debris from trees etc around the sunroofs and they wonder why they leak
probably the same people that never clean the house gutters

 

Yeah, if you get a ladder and look at the roof, it will be in a rather poor condition compared to the rest of the car given the exposure... No wonder so many roofs are fading, etc.

My long-long term solution? Will take the bars off, weld the holes, re-paint the body and cover the roof with the film. I am not super keen on keeping stuff on top anyway and when I overland, I carry only as much as I can comfortably fit into the truck.

 

It's kinda like it's missing a thick rubber ring gasket to form a water lock, you can probably find one in the plumbing section of a hardware store

 

The rubber gasket that you mention is sort of a part of the roof bar. I have no idea why LR decided to pursue the design as is... Many walls are double-walls, including the fixtures around the windshield, so patching one hole may not be enough as you don't see the other opening somewhere else. I suppose that is why it is hard to detect where some leaks may be coming from.

 

not mine. I wax it once a year