Window defective - How can something like this happen?

How old is the window? If under warranty, call the window manufacturer. Otherwise, could it be that some kind of lens effect formed inside? That the frame melted there?

It's all there. Fail, 6. :D Maybe from the moon? :D

The window is 8 years old. It happened that the Wickel heat radiator accidentally radiated against it a few weeks ago (low setting, 5 minutes), but actually further down towards the handle. It was turned away and I didn’t realize it at first because the baby was so active and also had a full diaper :D Maybe that was enough to cause it to break at the weakest point. Who knows… it looks ugly but probably has no effect.

The baby roaster is already the most likely cause. Where else should the necessary heat on the north side come from. The pane could very well have shattered there too.

The baby toaster is probably the most likely cause.

The ONLY one! @TE: you seem to be a joker.

Alright, but you could have thought of that earlier! Just kidding. So I’m not going to do anything about it, it is what it is.

That solves the case, Sherlock.