Place Order button flickers when selecting PayPlus payment method at checkout

Hi,

After updating to v8.1.8, we’ve noticed a visible issue during checkout.

When a customer selects the PayPlus payment method, the “Place Order” button briefly appears, disappears, and then reappears. The flicker lasts about a second and is noticeable every time the payment method is selected.

After investigating, I traced the behavior to a change introduced in assets/js/checkout.js. The payment method change handler now triggers a full checkout refresh whenever the selected payment method changes:

if (selectedPaymentMethod !== wc_checkout_form.selectedPaymentMethod) {
    $(document.body).trigger("payment_method_selected");
    $(document.body).trigger("update_checkout", { update_shipping_method: false });
}

The newly added update_checkout trigger causes WooCommerce to perform its AJAX order review refresh, which temporarily blocks and re-renders the #place_order button. As a result, users see the button appear → disappear → reappear.

By default, WooCommerce does not trigger update_checkout simply when switching payment methods, which is why this behavior was not present in previous versions.

I also noticed that another change in the same file replaced:

.prop("checked", true)

with:

.trigger("click")

This now invokes the payment method change handler directly, making the issue consistently reproducible.

Would it be possible to either:

• Remove the update_checkout trigger entirely, or
• Limit/debounce it so it only runs when the selected payment method actually affects order totals or checkout calculations?

The issue was not present in earlier versions and appears to have been introduced by these changes.

Environment:

• PayPlus for WooCommerce: v8.1.8
• WooCommerce: latest
• WordPress: latest

Thank you for looking into this.

• This topic was modified 1 week ago by Goran87.