Currently invalid attribute values, including invalid or empty values in CSS attributes in the 'style' attribute, could cause importing property with incorrect value, or NullReferenceException (the document cannot be imported).
Examples:
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<table width=”*”>
	<tr>
		<td>More Random Text</td>
	</tr>
</table>

The table is imported with 0 width. Instead the width should not be set.
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<table style="font-size:;">
	<tr>
		<td>More Random Text</td>
	</tr>
</table>

NullReferenceException is thrown.
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<p style='padding: 3px 3px 3xp 7px;'>test</p>

IndexOutOfRangeException is thrown.

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Workaround: replace the invalid values before import:
string importString = html.Replace("font-style: ;", "");