Maximizing client results in screen artifacts being left behind that partially obscure other non-client windows when they are maximized

[kwinter91]

Maximizing client results in screen artifacts being left behind that partially obscure other non-client windows when they are maximized.

While the non-client windows are not maximized they display correctly.

Would changing the client windowflags more than once cause this?

screenshot of result:
http://postimage.org/image/3pufmxj8/