Getting a similar html problem here - but otherwise things seem to be working so far on my test board..
Right after the text of the event, I get this:
*Event text here*<p><strong></strong></p>
<ul>
<li><a href="member.php?u=331">dodgechargerfan</a></li>
</ul>
Edit: If I click the "unattend" link in the calendar event, this gets left in the thread:
<p><strong></strong></p>
<p><i></i></p>
Hopefully, this helps steer someone towards a resolution. I'll keep digging to see what I can figure out, but I'm no expert.
BTW, Thanks for everyone's work on these plug-ins and the plug-in for the plug-ins.