Doubt about this exact case, but I've seen MD5 being (ab)used in a really weird ways, which I attributed to mindless "oh, I'll just use MD5 here, heard it's good for security!"
One particular case I remember was use of md5(md5(md5(unix_timestamp()))) to generate "secure" session tokens.
One particular case I remember was use of md5(md5(md5(unix_timestamp()))) to generate "secure" session tokens.