Exploding Window

[wacky window]

Wow, I had a weird thing happen last night around 11pm. my living room double paned window exploded. I even called the Sheriff dept. because I thought someone shot it out. turns out it was only the inside pane. The windows are only 7 years old and the temp outside was in the 60's. the window still moves in the track, so I don't think it was a bad install or settling. anyone have any suggestions?

 

[Bostitcher]

Tension because of a bad install maybe. Maybe it was under pressure and something just finally pushed it over the edge. dunno....strange.