Certain text, usually text which is not supported by default in Mac OS X, is not always fully displayed in either WebKit 40102 or Safari 3.1.2 . An example of this sort of thing is with ancient Chinese symbols, a sample of which can be found at the link above. You will only see the bug if your computer has fonts including Yijing hexagrams, Tai Xuan Jing symbols or Chinese counting rod numerals. The text can be temporarily seen in full if it is highlighted and un-highlighted. It will disappear again if it is scrolled away from.
I cannot reproduce this. Could you please attach a screenshot, and more detail about your configuration (including which non-default fonts you have)?
Created attachment 27123 [details]