no more problems
I did send it in last may. They did an update and change the battery one more time... since then not a single battery related problems, always a strong start up and I do not need to worry when opening and closing the automatic tailgate. I think I got a stronger version of the BMW battery but I haven't care to look at it since it perform well.
An "engineer" told me that as much as 10% of the new battery were junk from the factory... maybe that was the problem...
For me the update and a new battery did the trick, I hope it turn out ok for you too