Android : Amazon Receipts - IAP plugin for Unity

I have an app made with Unity in c# with subscriptions. I use the IAP plugin for Unity from Amazon. I want to handle a restore, so to test my inapps, I put my app on Live App Testing. I installed my app, and bought the subscription. Everything was ok, so I have deleted my app, and installed it again.

My issue is that I don't get any receipt in "purchaseUpdatesRequestSuccessfulEvent", the revoked AND the receipts lists are empty. Is this normal ? If not what should I do ? And if it is what can be done to get the receipts ?

Thanks for your help.