I'm using Shopware version 6.6.10.2 and have generated a ZUGFeRD e-invoice (pure XML format) for an order. In the preview within the admin panel, everything looks correct. However, once the document has been generated and I try to open or download it, I get the following error:

Cannot assign array to property Shopware\Core\Checkout\Document\DocumentConfiguration::$companyCountry of type ?Shopware\Core\System\Country\CountryEntity

I've tested this in multiple Shopware installations:

• No plugins were installed
• The default Shopware theme was used
• The issue occurs consistently with ZUGFeRD invoices

Has anyone encountered this error or knows what might be causing it? Is this a bug in the ZUGFeRD document generation or something misconfigured in the document setup?

Any help or insights would be appreciated!