[BUG] Duplicated Shipping Methods on PayPal Express Checkout After Updating Cart in Another Tab

[xclm2]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

There appears to be an issue causing duplicated shipping methods during the checkout process. Based on my testing, this seems to originate from Magento’s handling of cart updates while a PayPal Express Checkout session is active.

I’m not sure whether this behavior also occurs in a clean Magento setup or only in a customized environment.

Expected Behavior

Shipping methods should remain consistent and not duplicate, even if the cart contents are updated in another session or tab.

Steps To Reproduce

1. Add one product to the cart.
2. Go to the cart page and start PayPal Express Checkout.
3. In another browser tab, add one or more additional products to the cart.
4. Return to the PayPal checkout page and refresh it.

Environment

- OpenMage: 20.13.0
- php: 8.3

Anything else?

[sreichel]

Carrier code looks like its comming from an extension. Can you try to disable it and test again?