the rear window on my IS 350 has some sort of distortion when the sun hits it, it kinda looks like bubbles. it only shows up when the sun hits it at a certain angle. i dont have any tinting on it but im not sure if this is normal or not.

these are uv reducing windows and at certain angles and lighting you will see patterns in them,you will also see this with polarized sun glasses

Take your 2007 Lexi back to the dealer (look at the other 07"s) and if those others look like yours then it is the nature of the car ---- if those others don't have the problem then pleasantly suggest that you need to have the car company do the warranty work and replace the rear window....Those bubbles that you see are a sign of old glass and a poor lamination of the safety glass..good luck