To fix this, add the following code to the functions.php file of your Divi child theme.
(Note that using the Code Snippets plugin for this fix may not work)

/**
 * Fix GeoDirectory + Divi theme search empty results page.
 */
if ( ! function_exists( 'et_pb_is_pagebuilder_used' ) ) {
	function et_pb_is_pagebuilder_used( $page_id = 0 ) {
		if ( 0 === $page_id ) {
			$page_id = et_core_page_resource_get_the_ID();
		}

		global $wp_query;

		if ( empty( $page_id ) && ! empty( $wp_query ) && $wp_query->is_main_query() && function_exists( 'geodir_is_geodir_page' ) && geodir_is_geodir_page() ) {
			if ( geodir_is_page( 'search' ) ) {
				$page_id = geodir_search_page_id();
			} elseif ( geodir_is_page( 'archive' ) || geodir_is_page( 'post_type' ) ) {
				$page_id = geodir_archive_page_id( ( ! empty( $wp_query->query_vars['post_type'] ) ? $wp_query->query_vars['post_type'] : '' ) );
			}
		}

		return (
			'on' === get_post_meta( $page_id, '_et_pb_use_builder', true ) ||
			// Divi layout post type always use the builder
			'et_pb_layout' === get_post_type( $page_id ) ||
			// Extra Category post type always use the builder
			'layout' === get_post_type( $page_id )
		);
	}
}