When an entire building is curved, it acts like a huge concave mirror and can indeed damage whatever lies near the focus.
Individual windows acting as individual mirrors? Well, sure, but a flat mirror won't give you any more light on a surface than the original source. Necessarily LESS, of course.
Color me skeptical when it comes to individual flat windows being sufficiently concave to act as solar concentrators. A quick search shows that vacuum insulated glass has pillars every couple of inches between the 2 layers of glass to support the glazing against atmospheric pressure, limiting the concavity.