Created Unassigned: Issue when copying worksheet with cells having more complex formating [15043]

When copying worksheet from one excel package to other package, cells with more complex formating get distorted, e.g. "m3" (where "3" is a superscript) becomes

```
<r xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"><t>m</t></r><r xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"><rPr><vertAlign val="superscript" /><sz val="11" /><color theme="1" /><rFont val="Calibri" /><family val="2" /><charset val="186" /><scheme val="minor" /></rPr><t>3</t></r>
```

Using 4.0.0.1 version. Example project attached.