Our QA uncovered a bug and I have narrowed it down to something I can reproduce using the demo. It seems to occur when there are two adjacent paragraphs.
To reproduce:
1) Go to the online demo http://cutesoft.net/example/General.aspx
2) Switch to HTML and remove everything that is there, and paste in the following:
<STYLE type=text/css>
/*<![CDATA[*/
p.style-2 {font-weight: bold}
/*]]>*/
</STYLE>
<DIV class=style-2>
<TABLE>
<TR>
<TD>
<P>Paragraph one</P>
<P>Paragraph two</P>
</TD>
</TR>
</TABLE>
</DIV>
3) Switch back to Normal.
4) Highlight ALL of the text and change the font to red.
5) Now try to highlight all or part of the text and change it back to Automatic. It will not change.
The content where our QA ran into this was considerably more complex than this example, but you get the idea. With this example, if you do some additional twiddling, such as putting a carriage return at the end of the text then you can get the text to change back to Automatic, but the behavior is more strange with the more complex content that our QA was actually using - there were places where the text refused to change back to Automatic color and/or if you tried it would pull the paragraph below into the first paragraph and change it's color to red as it went along adding lots of <span> tags.