As Lexus don't make the unit they will need Pioneer to cooperate, on a device that is now superseded - and I suspect they have already seen the fault on several occasions as this is not a new issue.
Yes, I'd like to think Pioneer has this down.
It's likely to be a component breaking down - faulty batch, max. temp/voltage parameters too close to working temp/voltage, the product gets hotting than expected due to vehicle design etc.