These problems are related to image flickering or other distortions. This problem appears on factory systems with Mac OS X 10.5.2, indicating a potential bug in the OS revision.
On the other hand, it seems that this problem seems to affect only the QuickTime window in the foreground. In other words, the video that is played in the background is not affected by the flickering problem or any other distortion (either with another film or overlapping window).
As indicated in an entry posted in an Apple Discussion Board thread, this problem is now classified as “known” by Apple, telling users: “Apple is receiving reports similar to the problem described and we are investigating them. additional information such as Knowledge Base article, Software Update or Software Release “.
At the moment, it is known that Mac OS X 10.5.3 will include specific solutions to solve this problem, specifically eliminating “a problem related to graphics corruption.”