[wp-trac] [WordPress Trac] #64182: Critical Regression in WordPress 6.8+ Causing WooCommerce Cart Session Loss for Guest Users

[WordPress Trac]

#64182: Critical Regression in WordPress 6.8+ Causing WooCommerce Cart Session Loss
for Guest Users
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 Reporter:  mutanmohammad  |      Owner:  (none)
     Type:  defect (bug)   |     Status:  new
 Priority:  normal         |  Milestone:  Awaiting Review
Component:  General        |    Version:  6.8.3
 Severity:  blocker        |   Keywords:  needs-patch
  Focuses:                 |
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 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

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Ticket URL: <https://core.trac.wordpress.org/ticket/64182>
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