[css-writing-modes-3] Example of orthogonal flow

Hello,

While trying to create a few tests based on this example

  http://dev.w3.org/csswg/css-writing-modes-3/#example-30ac251e

  http://dev.w3.org/csswg/css-writing-modes-3/orthogonal.svg

I stumbled on an unusual rendering, at least, unexpected.

http://www.gtalbot.org/BrowserBugsSection/CSS3WritingModes/Orthogonal-flow-Example14-2.xht

IE11, Chrome 44 and Firefox 40 render that Orthogonal-flow-Example14-2 
test exactly the same way... which is a bit worrysome...

That is, div#next-sibling is rendered before div#next-sibling which 
seems, at least to me, unexpected and counter-intuitive. I think this 
rendering is wrong. I would expect p#second-parg to be laid out first 
and before div#next-sibling is rendered.

Comments are welcomed.

Gérard

P.S.: I haven't still had time to go through other emails and examples 
related to sub-section 7.3.x