For the patient who is passing for Denominator exception, the LIONC code is present in patient data as attached in the screenshots. In that case, the QRDA file also has the LIONC code and the code system for that denominator exception.

Can this LIONC code be empty (for IsNegation : true case) 

In our implementation, this was working fine. But we noticed that the code is empty from last few years when Denominator exception reason is added for a patient which is causing issue in QRDA 1 file generation. We are analyzing the root cause. We are not sure why it was handled like this in the past.
i.e. In our code we have a condition that code will be empty in case of isNegation is true

So we want to confirm that is it mandatory to have the LIONC code  & codeSystem in QRDA file as per standard? or it's not necessary? Or is there any  recent change done by Cypress to include the LIONC code?