In the help for the glossary block config, the text is displayed in a popup window as follows..

<b>Last modified entry</b> will always display the entry that was last modified, and <b>Random entry</b> will choose a new one at random every time. The option <b>Next entry</b> will cycle through the entries in order. This last option is especially useful when a number of days is also chosen, allowing you to make a <i>Quote of the week</i> or a <i>Tip of the day</i> that everyone sees.

Obviously the intention is that some terms will be bolded or italicised but because the text is being passed through the url rather than as a file, its not working.