Missing cart items in PRO version

Dear AIO-SEO team,

My name is Neven and I’m troubleshooting an issue of missing cart items for a client.

During the troubleshooting, we discovered orders were not being added to the cart.

I went ahead and disabled the plugin which got rid of the error. I traced the woocommerce/includes/cart-wc-cart.php with Xdebug for the add_to_cart() function and found some weird behavior. I couldn’t trace that back directly to AIO, but disabling the plugin confirmed it.

What I noticed was that the cart contents that are supposed to be set at the entry to the function are not set. set_quantity method is then supposed to increase the quantity based on the WP_Cart->cart_contents item data.

So what actually happens is that sometimes the quantity gets added when the cart_contents come in correctly and other times it doesn’t get added.

Adding to cart from the product page (not sure about product card AJAX behavior) often results in the following quantities showing: 0, 0, 1, 1, 2, 2, 2, 3, 3, … because the cart_data comes in “a version behind”

Are there any hooks you use to set WC_Cart->cart_contents over again in your plugin during this process?

I found zero woocommerce or wp_debug logs related to this, but feel free to double-check yourselves.

Tested with the latest version of WooCommerce (8.1.1) & AIO-SEO (4.4.5.1). I’ll be happy to send a system report of our site privately.

Kindly let me know if you need anything else.

With hopes of a successful resolution,
Neven