Should restore behaviour similar to the original snippet provided by Woo themselves

alternate_autocomplete_trigger.php

<?php 

function etp_woo_use_alternate_autocomplete_trigger() {
    if ( ! class_exists( 'Tribe__Tickets_Plus__Commerce__WooCommerce__Main' ) ) {
        return;
    }

    $woo_provider = Tribe__Tickets_Plus__Commerce__WooCommerce__Main::get_instance();

    remove_action( 'woocommerce_payment_successful_result', array( $woo_provider, 'maybe_complete_order' ) );
    add_action( 'woocommerce_thankyou', 'etp_woo_alternate_autocomplete_listener' );
}

function etp_woo_alternate_autocomplete_listener( $order_id ) {
    $woo_provider = Tribe__Tickets_Plus__Commerce__WooCommerce__Main::get_instance();
    $woo_provider->maybe_complete_order( array(), $order_id );
}

add_action( 'init', 'etp_woo_use_alternate_autocomplete_trigger' );