Created attachment 218007 [details]
A normal flow region overlaps a floated region, and render its content on top of the floated region.
My personal expectation would be that the content flowed in the normal-flow region would not render on top of the floated region. This should also be the case, since regions are supposed to be block formatting context, so they (or their contents) should automatically clear other floats outside of them
Fixed by https://bugs.webkit.org/show_bug.cgi?id=133545
*** This bug has been marked as a duplicate of bug 133545 ***