PayPal payment throws an error on redirection back to the shop

[plewandowski]

How to reproduce it?

• buy anything
• select safer pay as payment method
• select PayPal when redirected to payment gate
• make successful payment
• error 500 on redirection back to the shop

Payment status remains "new".

More details

PHP Error:

Got error 'PHP message: PHP Warning:  Undefined array key "AcquirerReference" in /var/www/shop/vendor/commerce-weavers/sylius-saferpay-plugin/src/Client/ValueObject/Body/Transaction.php on line 101', referer: https://test.saferpay.com/

Exception:

{
  "exception": {
    "class": "TypeError",
    "message": "CommerceWeavers\\SyliusSaferpayPlugin\\Client\\ValueObject\\Body\\Transaction::__construct(): Argument #7 ($acquirerReference) must be of type string, null given, called in /var/www/shop/vendor/commerce-weavers/sylius-saferpay-plugin/src/Client/ValueObject/Body/Transaction.php on line 104",
    "code": 0,
    "file": "/var/www/shop/vendor/commerce-weavers/sylius-saferpay-plugin/src/Client/ValueObject/Body/Transaction.php:12"
  }
}

Unfortunately there's no entry in log table for return request (perhaps failed before logging).