If anything, it's something else that could go wrong in the car's software.
No, Lexus isn't immune to software problems, I had an IS250 that would backfire a lot due to (very) faulty powertrain software running the valve timing wayyy too far one way (don't remember if it was too advanced or reduced).
As far as standing behind the car, well, yes, the dealer did accept a swap for an RX330. :)