renault megan 2004 rear window smashed?

Could be, but more likely atmospheric/weather conditions. Exactly the same thing happened to a Renault Espace rear tailgate window that I owned.

A couple of years ago the driver's door window did the same on my VW Golf Estate.

Fortunately my car insurance has glass cover and, although I had to pay an excess, my NCD was not affected.

ChicksFan
December 2014