Greetings Deavas,
With the 3.7 update, there has been a change to the Battlegrounds. If 12 players are not present at the start of the Battleground, the Battleground will end immediately and you will have to register again.
We listened to your feedback on this matter and are already in contact with NCSoft. We hope to be able to provide you with an update on this in the near future.
Thank you for your understanding and your feedback.
Your AION Team