HiI was looking at your pics...looks like the top of the rear hatch just above the pneumatic arm...the build style is totally different than the north american version. Is that piece there a fold of caulking like filler that sits over the actual seam? That is what it looks like
You can see from the pic the difference between the two cars...I would have to say that if what is underneath yours is the same as ours...you have nothing to worry about...the actual metal fold seams/welds are totally solid.
My Subaru Outback 2011 diesel is developing these stress cracks in the roof at the rear near the rear door hinges. Are they similar to your experience? 175,000km second owner