When creating a glossary, in its summary, people tend to use tags such as <p>, <ul>, <ol> or even <div> because they want to create paragraphs. The problem is that when someone watches a glossary, its summary is wrapped with the <p> tag, which doesnt allow does tags inside. Example of a normal generated summary:
<div id="intro" class="generalbox box">
<p>
This is a glossary test
</p>
</div>

Note that "This glossary test" was written without the <p> tag in the summary editor, but if we want to create two paragrapas in the summary, such as:
<p>This is glossary test</p>
<p>This are its specifications</p>

This will be translated to:
<div id="intro" class="generalbox box"><p>
<p>This is glossary test</p>
<p>This are its specifications</p>
</p</div>

Which is, indeed, wrong.

The easiest solution is to change the outer <p> for a <div> tag in the code.