Phone field not translated on checkut page

On the checkout page, the fields are translated to the site language (Danish), except for one field. If you check the box to enter a shipping address that’s different from the billing address, some extra field will appear, including a Phone field. The text ‘Phone’ is for some reason not translated. The Phone field in the billing address section above is translated just fine to Danish (Telefon).
How can I translate the untranslated Phone field?

I have Loco Translate plugin installed, and searching for the string in Woocommerce, it seems like it is translated correctly. The string doesn’t appear in the theme translation (Storefront).

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