This got solved after some mailing back and fro, but part of the solution merits to be documented.
Problem was the the javascript in the sidebar relied on jquery. Once both the sidebar-js and jquery were excluded, all worked OK.
But taking it one step further; as the sidebar-jquery only was shown on one particular case, I propsed the following Autoptimize-API based code to only execute the exclusion on a particular page (e.g. on http://blog.url.net/funtastic/);
add_filter('autoptimize_filter_js_exclude','herold_ao_override_jsexclude',10,1);
function herold_ao_override_jsexclude($exclude) {
if (strpos($_SERVER['REQUEST_URI'],'funtastic')!==false) {
return $exclude.", goal.js, jquery.min.js";
} else {
return $exclude;
}
}