Well, got the X5 back today with the leak supposedly fixed. We'll see the first good thunderstorm we get! The issue is related to welds in the tailgate area. Basically, under the spoiler (proper term?) along the top of the tailgate, there are welds between two sheets of metal. One of those welds was bad from the factory. Fortunately everything is under the spoiler so no visible damage from welding. My service advisor indicates there is no recall or SIB about this but we were the third X5 this dealer has seen with the issue.