I have checked the issue with the latest 10.3 Beta (14E5230e) The time since the last update is now showing correctly, so this part of the problem is fixed. However, one problem still remains. If there are two cards installed with different serial numbers but with the same passtypeID, the notification for one card still overwrites perevious notification for another card.
Scenario:
1. Install card #1 and card #2 in Wallet. Same passtypeid
2. Send push to card #1
3. Push appears in notification center
4. Do not clear notification for card #1 and wait couple of minutes
5. Send push to card #2
6. Notification is shown in notification center for card #2, overwriting previous notification for card #1. The time of notification is correctly shown as 'now'
7. When tap on this notification, Wallet opens and shows card #2
So the conclusion is that the earlier notifications are lost, and user cannot open relevant card by tapping the notification. Only the card updated last has notification shown and can be opened by tapping the notification