Xamarin Forms, button needs two taps before anything happens

Hi All

I am having a bit of a strange problem, not sure if anyone else has had the same problem, when you initially tap the button, the button goes a darker shade (highlighted), you then have to tap it a second time before the code actually executes.

void AttendingClicked(object sender, System.EventArgs e)
{

        try
        {

        }
        catch (Exception ex)
        {

        }

    }