What happens to mine is the glass fractured and get sucked into the "chamber" like it got vacuumed inward. It doesn't look like it has an impact, so either thermal expansion (1/2 the glass is under the sun the other 1/2 isn't), or some extreme heat delta between different part of the window.
Found out that it is a Mercer Window part 030-034, or something like that. The window was installed way back before my kids were borned when our neighbor's construction company shot a nail through the old window and the replacement guy ruined the old window frame's installation. My guess is this would be at least from 12-14 years ago so most likely out of warranty (and Mercer Windows was out of business and inventories / equipment sold to VPI windows).
This window is on the 2/F bathroom, so it is definitely not a DIY (I have no ladder this tall), should I be looking for a "Window Fitter"? or a glass company? At the moment I think I might be able to get by with maybe something covering up the broken glass still stuck there (some actually popped into the bathtub), like plexiglass or transparent packaging tapes.
