AnalyseExpense Api: "Leergut" with negative price not shown as Line Item

I am working on automated analysis of receipts. Obviously, the AnalyseExpense feature of Textract seems like the way to go. Although it is targeted at English documents, I am still getting reasonable results for German receipts as well (which is my main use case).

In Germany there is a deposit system and if you bring your empty containers ("Leergut") back to a supermarket you get the deposit refunded. This usually shows up as a line item with a negative price. If I send such receipts to Textract, I repeatedly do not receive these line items back where I would expect them. I see the word and the negative amounts inside the Blocks array, but I do not see them inside the LineItems array.

Is this intentional? Is there a roadmap when to expect German support in AnalyseExpense?