I think this is deliberate on the part of the plugin authors, but only the time shows up for the first day of a multi-day event, in Agenda view. The idea being, I suppose, that the first day is displayed in the nice little date box off to the left - but it's confusing to visitors, because they just see this:
7:00 pm – May 12, 2013 @ 6:00 pm
They don't connect it with the May 10 in the little date box on the left.
Suspect I'm going to have to get into the code to change this, but I would recommend changing this in future versions.