What brand of window? What type of window? What type of Glass? What direction is the window facing? Is this "double reflection" showing all the time? What makes you believe one of the panes of glass is "bowed"? Who was the installer, a contractor or a window professional?

Double pane windows have 2 reflections, because there are two panes of glass. But if the reflections are far apart or much bigger or smaller than the other maybe there's an issue?

Hmmm.... do the reflections look the same? Some paranormal activity perhaps? :P

The reflections are different sizes. If you move from side to side in front of the window one reflection moves and the other stays in approximately the same position. The double reflection is always present. I have many double paned windows in my home and have looked at many at my work place. There may be two reflections in those windows but they are almost indiscernible. The window was installed by a business which specializes in window replacements and installations.

If there is some deflection in the glass, this can happen.

Can you snap a picture of it?