We also found this this happened for the first time today. Exactly the same issue except our download_id was nil. Weird thing is that the bundle_id isn't just null but its the string "null"
Also note: the receipt from the users device was correct but this issue was present in the unified receipt sent from the App Store INITIAL_BUY event callback.
I am pretty certain it's a bug on Apple's end but nothing conclusive yet.
Topic:
App Store Distribution & Marketing
SubTopic:
General
Tags: