When scrolling the window of the update-manager I get a distorted display on two quite different machines. Probably caused by really having some more entries in it than the "usual" user. Since the Update Manager is the sole program showing this strange behaveour I assume that it is related to the way the output is made. Both machines (win vista and win 7) are on actual microsoft update, effect seen the first time some months ago.
See attached screenshot
We've noticed this as well and are working with our development teams to resolve for the next release. Thank you for pointing this out and please let us know if you see anything else.