Created Unassigned: Pasting into source tab adds in non-breaking spaces [27940]

Why, when i paste the following code into the source tab, then switch to the design view, and then back again, does the editor insert non-breaking spaces everywhere?

```
<table style="margin: 20px auto; width: 640px;">
<tbody>
<tr>
<td>
<a href="http://www.website.com" title="" target="_blank">
<img src="http://www.website.com/Images/imagefile.png" style="width: 100%;" alt="ALT" /></a>
</td>
</tr>
<tr>
<td style="font-family: arial,helvetica,sans-serif; color: #282828; font-size: 16px; padding: 20px;">
<p>
Hi John,</p>
<p>
One line of text.</p>
<p>
Second line of text.</p>
<p>
Another line of text</p>
<div>
<a href="http://www.website.com/en/Brand/brand.aspx?SortBy=NewestDesc" title="title tag"
target="_blank">
<img src="http://www.wesbite.com/Images/imagefile2.jpg" style="width: 200px;
margin-top: 20px;" alt="Another alt" /></a></div>
<p>
Regards,<br />
The Wesbite Team</p>
<p>
'Some text pretending to be a quote.'</p>
</td>
</tr>
</tbody>
</table>
```

I've attached screenshots of what I'm seeing in a brand new web application project, and the ACT installed via nuget