Thanks Whatamidoing for your reply. I will reply to both place so people can follow this case.
Our wiki is run on Ubuntu 14.04.5 LTS server. Parsoid version is 0.6.1, Mediawiki version is 1.27.1 LTS and VisualEditor version is 0.1.0.
This is a private Wiki, but i have change it to a public Wiki and the problem is still there.
We have some extensions, but i will not list them (except if you need it), because when i disable them all, this does not solve the problem.
I don't think the problem is related to parsoid, because, when i troubleshoot parsoid and show the page in problem (http://servername:8142/localhost/v3/page/html/Test/), everithing seems to work fine and there is no error un parsoid log.
The only way i get VisualEditor to work with a page that have an image aligment, is when i put the Wiki in english. Our Wiki is in french.
When i inspect the code with Chrome Debugger, i get this error : Uncaught TypeError: Cannot read property 'constructor' of null at Object.oo.cloneObject.
I have also report this bug at https://phabricator.wikimedia.org/T123471.
Let me know if i can test something to help troubleshoot.