Maybe the outermost layers just transferred the energy to the innermost, which exploded tiny shards of glass? In general though, I agree, weird.
A projectile hits the armor and doesn't penetrate it, but the armor inside still fragments and injured the operators
https://www.reddit.com/r/ThatLookedExpensive/comments/1oalnx...
This was also adopted by The Expanse, where the interiors of ships (particularly war ships) are coated in antispalling coatings.
Might have been a mention on the Agatha King.
But the coloration in the window sure suggests spalling. I’m surprised the tempered glass did that much damage. That takes a lot of velocity. Which is probably why they aren’t thinking bird.