https://macshot.de/html/multicolumn-overflow.html shows the one table exploded into separate parts whereas https://macshot.de/html/multicolumn-without-overflow.html is displayed correctly. Rüdiger So with Safari 3.1.2 and even Nightly build r40738.
Created attachment 27480 [details] With overflow
Created attachment 27481 [details] Without overflow
This has been fixed now by the changes to make overflow self-painting.