The problem is that a growing number of banks now use app notifications to approve online payments. (UK based personally, so may be different elsewhere)
What happens is this...
1. You attempt a payment in some app.
2. It shows the 3D Secure screen from your banking provider telling you that you need to approve via the notification.
3. You switch to your banking app to approve.
4. You return to the app you were trying to pay on.
5. The app restarts to it's home screen and doesn't seem to know it was supposed to be in the middle of a payment flow.
There are several apps that have literally become useless to me because I can no longer complete payments on them.
What I guess might be happening is developers are testing the payment flows with dummy cards that don't require app authentication, and just don't know about these types of card authentication flows.
If your app takes mobile card payment, it absolutely needs to be able to deal with a switch out of the app, and recovery to the middle of the payment flow. Please spread the word and make sure this scenario is tested for. You will be losing customers over this without knowing.
It could also be more of a problem on lower end phones with less memory that are more aggressive about shutting apps rather than keeping them active in memory.
