Facebook credits callback request is not always including the 'order_info' parameter

I have successful FB Credits integration, which receives many requests per day. But sometimes 3 or 4 times a day, my callback receives a 'payments_get_items' without the 'order_info' parameter.

Anybody has had the same problem? Or knows whi开发者_StackOverflow社区ch cases could generate that kind of request? I am wondering if I can simply ignore the error.

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This was an implementation error, which was no setting the order_info parameter correctly on some browsers. Seems that order_info is not mandatory at all, which makes sense to simplify its use.