Describe the bug

I've been seeing some customers reporting issues with a few text strings on their checkout reverting back to English when they update WooCommerce to 10.1.

Some examples:

10123480-a8c
10105188- a8c

To Reproduce

Steps to reproduce the behavior:

• Install WordPress and change it to a non-English language.
• Install a previous WooCommerce version (e.g. 10.0.4)
• Change to Storefront theme and add a test product.
• Go to checkout and check the translations, they should be working properly.
• Update WooCommerce to version 10.1.
• Go back to Checkout, and some text strings won't be translated anymore, they'll be in english.

Expected behavior

Checkout to stay translated to default WP language after WooCommerce update, instead of reverting back to English.

Screenshots

I've recorded a video in a local test environment where I show this issue: https://share.cleanshot.com/qJ3yFZqJ

• My setup is clean, just Storefront theme and WooCommerce.
• I installed WP-Rollback to show that once I downgrade WooCommerce back to 10.0.4 and update translations at Dashboard > Updates, the checkout translations work again. As soon as the plugin is updated again, translations get affected again.

Environment

Please fill out any of the below that applies

Operating System/Device

• Windows
• MacOS
• Linux
• iPhone
• Samsung
• Other (add in additional context field)

Version: Add the Desktop OS and/or Device version(s) here

Browser

• Desktop Edge
• Desktop Chrome/Chromium
• Desktop Safari
• Mobile Edge
• Mobile Chrome/Chromium
• Mobile Safari
• Other (add in additional context field)

Version: Add the browser version(s) here.

Additional context

This issue will be published publicly, add system status report and internal links to Slack thread after issue created.

SystemStatusReport_localhost_2025-08-18T15-56-21.txt