The following html/template template:

<script type="text/template">{{"Hello"}}!</script>
<script TYPE="text/template">{{"Hello"}}!</script>

produces the output

<script type="text/template">Hello!</script>
<script TYPE="text/template">"Hello"!</script>

Note that the case of the "type" attribute name affects the type of escaping applied to the body of the script element. This goes against the HTML spec, which says that attribute names are case-insensitive.

The source of this bug is in html/template's state machine (see here), where the attribute name found in the template is compared with the string literal "type" without first converting the attribute name to lowercase. However, when the attribute name is used to determine the attribute type, it is converted to lower case.