Some guidance from the support team helped me fins a function causing the problem.
Delete it and everything is up and running
function my_acf_flexible_content_layout_title( $title, $field, $layout, $i ) {
// remove layout title from text
$title = ”;
// load text sub field
if( $text = get_sub_field(‘section_lable’) ) {
$title .= ‘<h4 style=”margin: -20px 30px 0;”>’ . $text . ‘</h4>’;
}
// return
return $title;
}
// name
add_filter(‘acf/fields/flexible_content/layout_title/name=section’, ‘my_acf_flexible_content_layout_title’, 0, 0);
add_filter(‘acf/fields/flexible_content/layout_title/name=footer_section’, ‘my_acf_flexible_content_layout_title’, 0, 0);