As Chris says rust is common around the chrome strip and also around the Handle/badge section on the tail gate. Both are caused by grit and dirt getting between the chrome strip and body and the joint between the tail gate and the plastic section which houses the handle and number plate light.
I had both done last year under warranty. Another area to watch is under the number plate I noticed rust spots starting to appear just before the tail gate was resprayed.
When I pick up my new Antara next week I be will putting a strip of clear film between the trim parts and the paintwork to make sure it doesnt happen with this one. I will also make sure the centre caps dont rub on the alloys and starts the lacquer flaking which is also another problem.
I had the same issue with rust appearing on the corners of my tailgate and when it was inspected at the dealership the warranty manager looked at a few other common spots including at the number plate and chrome strip and he decided they would respray the entire tailgate and replace the chrome strip and plastic section with the handle.
This was done under warranty on my 2012 plate Antara
Thanks for that will be taking it to the dealer as soon as I can, the only problem I can see is the fact that my car is Snowflake White and I have been told that this colour has been discontinued and may not be available any longer.........Edited by: vauxhallbitz