Linkbutton in dynamically loaded user control does not handle command event

I have a user control that is dynamically added to a placeholder control inside an update panel in my main page.  The user control has a linkbutton where I try to handle its Command event.  The first time the link button is clicked after the user control loads, the form posts back but the command event handler does not execute, although the user control is still on the screen.  The second and subsequent times the link button is clicked it works perfectly.  When the user control first loads and I mouse over the link button, the browser status bar says: javascript: __doPostBack('ctl08$lbTest','').  After the first click, when I mouseover the link button the browser status bar shows javascript: __doPostBack('ctl07$lbTest','').  Why the changed in id, I can't figure but it must be why it is not hitting the event handler the first time it's clicked.  Here is the cs code that loads the user control:
 
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