Yes, mine did the exact same thing, looked the same way, and oddly, under the same circumstances. At lunch, went in to a store and came out about 20min later to a perfectly shattered sunroof. This is in TX. Long story short, at first the LR dealership said that they could not cover it under warranty when I call them. If figured as much. However, when I took my glass out and carefully brought it to them, they examined it closely.
After looking at it closely out of the truck, they said that they would cover it under warranty. If I recall, it would have been about $628 if they didn't cover it.
It is extremely easy to take the glass out yourself. Just a few screws. I put painters tape on it in some places to transport it. They swapped mine out no charge.
Look for any point of impact. If one is there, it will be obvious. Mine had none.
By the way, vandalism to a sunroof is not likely. Why would a vandal take the time to get up to the top of the LR3 and smash just the sunroof. Lots of other easier more exciting glass to break other than the roof.