In App Purchase Restore Incomplete, does not match receipt

[[SKPaymentQueue defaultQueue] restoreCompletedTransactions]

in the sandbox consistently returns an incomplete list of transactions. As I repeatedly restore, product ids get dropped, such that I can only restore a handful out of 20 purchased non-consumable IAPs. Even stranger is that the refreshed app receipt is correct; the list of restored transactions does not match the app recipt.

Has anyone been experiencing this problem lately? This seems to be a bug with the sandbox servers, it will be good if I can get some kind of confirmation that this doesn't happen with live servers.