I'm not quite sure when this started happening, but I'm seeing the HTML entity code for the hyphen character when used in the placemark title when it is between whitespace characters. For example:
DevConnections Spring 2012 - March 26-29, 2012
DevConnections Spring 2012 &%8211; March 26-29, 2012
However, if I change the title to this:
DevConnections Spring 2012-March 26-29, 2012
It displays properly.
You can see the issue here: