Critical Regression in WordPress 6.8+ Causing WooCommerce Cart Session Loss for Guest Users

[mutanmohammad]

Hello WordPress Team,

I am writing to report a critical, reproducible bug that appears to originate from recent WordPress core updates (starting with version 6.8). This bug causes WooCommerce cart sessions for guest users to be automatically cleared immediately after an item is added — severely impacting e-commerce functionality and resulting in lost sales. It's appearing sometimes not for every added product.

When a guest user adds a variable product to the cart from the Main/Shop/Catalog page (using any variation-selection method), the item is added successfully, then automatically removed from the cart without user action.

This behavior occurs regardless of the variation swatches plugin used, and it disappears entirely when downgrading WordPress to version 6.7.3 (even before 6.7.4 existed).
That confirms the issue is introduced at the WordPress level.

Diagnostic Steps Performed by me:

Plugin Isolation: Only WooCommerce active and any swatch plugin to test the scenario. The issue persisted.

Theme Check: Tested with other themes, my current theme Astra and other like (Kadence, Blocksy). The issue persisted.

Browser Check: Tested in Chrome, Edge, and Opera in Incognito Mode. The issue persisted.

Host Check (Staging): Tested on a clean staging site with Hostinger. The issue persisted.

Host Check (Alternative Host): Migrated the full setup to Pantheon (entirely different stack). The issue persisted there as well.

Reproduced the issue on desktop and android.

WordPress Downgrade Test: Downgrading from 6.8.x → 6.7.3 immediately resolves the issue 100% of the time.

Example of this issue at my end:

Video 1: Bug occurring on Hostinger environment
​https://www.loom.com/share/58cf61fba972474d897164a29728ba1b?sid=f6a3d77a-9e91-424e-822e-981b137b0627

Video 2: Same issue on clean Pantheon environment
​https://www.loom.com/share/49cc517dce294d33b50850e4473c54e2

You can reproduce the issue at this staging site: ​https://staging.yazur.shop/product-category/winter-collection/
⚠️ Try adding products multiple times; the issue is inconsistent and does not occur with every product added.

Please escalate this to your development team immediately. This bug is actively preventing sales, and require a quick action.

Thank you for your prompt attention.

Best regards,
Mohammad Mutan

[westonruter]

@mutanmohammad did you report this issue to WooCommerce?

[mutanmohammad]

Thank you for your prompt response.

Yes I reported it to woocommerce, they investigated the issue and said it's not from their end.

I tried downgrading the woocommerce version, nothing fixed the issue except downgrading the wordpress version.

Here is where I reported the issue to Woocommerce, ​https://wordpress.org/support/topic/system-removes-the-newly-added-item-from-the-cart-automatically/

Let me know for any further information.

[mutanmohammad]

Hi @westonruter and team

Could you please provide an update on the status of this issue or an estimated timeline for a fix? Any temporary workaround in the meantime would also be greatly appreciated.

[jorbin]

Based on the ​linked WooCommerce thread, it sounds like this is an issue with Variation Swatches for WooCommerce, not an issue with WordPress core. As such, I think this can be closed as invalid.

[mutanmohammad]

@jorbin

As outlined in my full email, the evidence confirms this is not a swatches plugin issues.

I've confirmed the issue persists with different swatches plugins and still occurs when working on other variations.

The critical finding is that the behavior stops immediately when downgrading WordPress to 6.7.3.

Could you share the steps taken during your investigation so I can better understand your conclusion?

[jorbin]

This is a bug tracker, we don't have access to any emails you may have sent to someone.

The reasons I don't believe this is a core issue:

1. There is no demonstrated problem with core. The problem you are describing only presents itself with 3rd party plugins which are responsible for ensuring they work with each version of WordPress. Can you demonstrate an issue with the core WordPress software that doesn't rely on 3rd party plugins?
2. There is no specific changeset that can be pointed to as causing the problem. If you want to do a git bisect and find what you believe to be the problematic issue with WordPress Core, please do so and share your findings here.
3. If this was a critical issue with WordPress core, it would have been reported sooner than ~200 days after the release of 6.8.