Like the now botched up blue clicky maker this is a not-thought-of concequence of moving the Mudcat page to the secure https web protocol.

The 'Lyrics & Knowledge Search' form is explicitely calling 'http://search.mudcat.org/@NewSSResults.cfm' and not 'https://search.mudcat.org/@NewSSResults.cfm', so the web browser is complaining about going back to an insecure protocol.

The 'DT Lyrics' form below that is calling the script '/title.cfm' which is a page on the same server and there is no access protocol specified, so the browser can use the same https protocol and you don't get the security warning.