Well, not exactly missing favicon, Is your own favicon replaced by Blogger favicon? There had been many complaints about this at favicon for your blog as well as at a newer post free favicon generator and host and I myself experienced the problem.
Fix for missing favicon
Just move your codes for the favicon from it original position in the template to just after ]]> </b:skin>and just before , preview and if everything looks all right, save template.Actually, I left the original code for the favicon in its original place and copy-paste to just after ]]></b:skin> and just before
This is how that section of the template looks like after the fix:
1st Step: find this html code CTRL+F or ]]></b:skin> see the Picture Below
]]></b:skin>
<!-- iconj.com dynamic favicon code -->
<link href='http://www.iconj.com/favicon.php?user=manature' rel='shortcut icon' type='image/x-icon'/>
<link href='http://www.iconj.com/favicon2.php?user=manature' rel='icon' type='image/gif'/>
<!-- end of iconj.com dynamic favicon code -->
<link href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHaeJpAyPRLKZAumkyjvCKHIPcmzzbf7ewxeBrgJeFbxJ5a-uf2-RAR7L1QY19i2k8sIp3_SkZWkh6VtCqCW3X20PJR8CQLvrBD9qUs5NS6NrhhOFHmZGS0DFu2GD-DMoSfbSQtf5a789a/s1600/n.ico' rel='shortcut icon' type='image/vnd.microsoft.icon'/>
</head>
<body>
Paste the favicon codes immediately after and Your Done: Free Favicon Hosting and Icon Generator