iPhone In App Purchase prompting login on addTransactionObserver on completely new device with new user

I am calling addTransactionObserver: in my AppDelegate's didFinishLaunching method, and it immediately prompts the user to either log in to their iTunes account, or to input the password if they are already logged in. This happens to new users who have never installed the app before. If they input the password, nothing happens, and the app is fine, but they are then prompted for their password again when they want to buy something. Regardless, the app shouldn't be asking a user to log in to their iTunes account when all it has done is launch.

I know that there are issues that can arise from not calling finishTransaction: where the transaction can get stuck in a weird state and prompt the user to log in until it is finished. However, in my case, I have deleted ALL sandbox test users, created a brand new one, installed the app fresh, and it still immediately prompts me to log in, or input my password if I already have logged in. I have factory reset the device, and it still behaves this way.

I think it may be some old unfinished transactions that were associated with other test user accounts, but since they are deleted, I have no way of checking. Is there something else I can do to stop the login prompt from showing?