I have exactly the same problem on my 2005 Sienna XLE AWD. Please take the time to post your comments and affected wheel photos here: http://www.nuckleslaw.com/software-negotiations-expert/toyota-alloy-wheels-bubbling-toyota-quality-concerns/
I am trying to convince Toyota that this is a widespread problem and that it should accept responsibility.
In numbers, we can make a difference!
Demiglaz (Wisconsin USA)