Browsers occasionally mess up the favicon cache and display the wrong icon. Emptying the cache and clearing the history typically resolve the problem.
There are two ways to specify a favicon. You can put one at the top of your site or you can specific a link in the header section of the page. The latter allows you to vary the favicon across a web site. I'm assuming that when the podcast board was setup the choice was made to use the favicon from the disunplugged blog site.