I hit this bug occasionally on Win 7 in the past but did not bother to investigate further.
However, last week I noticed something while I was testing my terminal emulator on Windows:
When I minimized the window and then restore it, the terminal display has been damaged.
It turned out that Windows minimize button is really minimizing the window (i.e it is resizing the window on minimize event. AFAIK other windows managers don't do this.)