There have certainly been 12V battery issues on some early Leaf years but that appears to be due to poor charging algorithms or maybe unanticipated use cases (lots of short trips, no highway driving). There is nothing technologically challenging about keeping a 12V lead acid battery healthy in an EV and while there have been problems, I'd say the majority of users never give it a thought and have no issues.
Probably the biggest difference between an ICE and an EV in this regard is that in an ICE, it's usually pretty obvious when the 12V battery is failing (trouble starting) while in an EV the first symptom is usually a total failure of the entire car with no remedy except a tow and a new battery. Some sort of early warning of 12V battery weakness would not be hard to implement in firmware and could solve this problem easily. We'll see who does it first.
