Formatting lost for 1 username but not the other

Hello,

I have a person whose task is to help me with co-editing blog posts, however this username has a big problem, parts of the post formatting is lost after he edits posts. And we have no idea why ?!?
Could I ask for help with this, please ?

The trivial styling loss :
<p style="text-align: center;">
, once edited by my helper, becomes
<p style="text-align: center">

Also, we noticed recently that noscript has the same issue.

If I (as I, the username without problems) write

<script language="javascript" type="text/javascript">
document.write('Disable your JavaScript then reload this page');
</script>
<noscript>Your browser doesn't support JavaScript or you have disabled JavaScript. Therefore, here's alternative content...</noscript>

it becomes, once the post is saved by me :
<script type=”text/javascript” language=”javascript”>
// <![CDATA[document.write(‘Disable your JavaScript then reload this page’); // ]]>
</script>
<noscript>Your browser doesn’t support JavaScript or you have disabled JavaScript. Therefore, here’s alternative content…</noscript>

So far, so good. I don’t see why CDATA is added, but if wordpress wants it, I don’t object, it still works after all.
But when my helper edits the post and saves, only the “noscript” part remains (the entire javascript is gone), an loses its <noscript> ... </noscript> tags.

I’m at a loss, I have no idea why that happens.

What we tried :
– tested on another blog (also on my server) : same issue.
– created another username for the helper : same issue.
– helper tested with other browsers, including IE, FF17, Chrome : same issue.
We noticed it first under WP3.7, and it continued with WP3.8. Maybe it’s dating even farer back, we can’t tell.

Would you have an idea about what may cause this issue, and how to solve it, please ?

Thank you so much if you can help ??