Steps to reproduce: 1) Open http://www.auriga.ru 2) Mouse over "Domain expertise" menu below the large graphic. 3) Wait a little for Flash below it to finish animating. 4) Move the mouse down. Results: parts of the Flash image become visible as you move the mouse down. I can only reproduce this on Leopard, Tiger appears unaffected.
<rdar://problem/5619302>
This is resolved in an updated Flash Player plugin, available from Adobe.