I received your URL and checked your homepage. No duplicated favicon. With my own IE, I see your up-to-date favicon (white “Y”). So it must come from a classic caching issue.
Now, two possibilities (yeah, I really like bullet lists ?? ):
– Your site is under development and the “grand opening” didn’t happen yet. In that case, no problem: only your browser is impacted. Your future visitors don’t know your old icon and will load the new one, as expected. In that case, you have nothing to do.
– Your site is already in production, and your existing visitors may suffer from the same caching issue. In that case, I advice you to generate your favicon again. But this time, in addition to the settings you already selected during your first generation (background color, etc), look at the “Version/Refresh” tab in the favicon options. Select the second option, “The web site is already in production…”. That will force your visitors’s browsers to reload the favicon.