This page renders incorrectly using a local debug build of WebKit r20683 with Safari 2.0.4 (419.3) on Mac OS X 10.4.9 (8P135): http://en.wikipedia.org/wiki/Wikipedia:Tips. Works correctly with Firefox 2.0.0.3.
Created attachment 13937 [details] Screenshot of rendering issue
Sadly, this is not a regression from shipping Safari 2.0.4 (419.3) on Mac OS X 10.4.9 (8P135).
Created attachment 13942 [details] Reduction
I am not able to reproduce this bug in Safari Technical Preview 152 using attached test case and both boxes don't overlap and all other browsers (Chrome Canary 107 and Firefox Nightly 106) also match with Safari behavior. Since all browsers are making each other, I am going to mark this as "RESOLVED CONFIGURATION CHANGED". Please reopen, if you think it is still an issue with updated test case. Thanks!