After flight mode deactivation, only the last push send is received. This is the behaviour of the Apple / APNS push API, it is independent of Batch.
See the technical documentation here.
By default Batch offers the same behaviour as iOS, but you have two ways to control it.
1. via the "Collapse Key"
You can choose on the dashboard to ensure that all pushes are received:
From the creation campaign form > Advanced Settings > disable the Collapse Key
From the settings of your Android app > Push Settings > Default push settings > disable the Collapse Key and click on "Update push settings" button
2. via APIs
You can set up specific behaviour or a mix of behaviour, for instance:
all the notifications are kept and therefore will be delivered
all the transactional pushes are delivered but only the last marketing push.
💡 if you set up a TTL on your push or in your app settings, if the push is not sent in the fixed limit, the push will never be sent.