40kWh Leaf has very basic battery overheat protection, similar to previous Leafs.
Throttled charging/regen and power output.
This also happened on 24kWh and 30kWh Leafs, but at much higher temperatures.
Something like 50-55C before charging current is reduced.
New battery supplier demanded more protection and Nissan had to agree.
And this is how RapidGate came to life.
New "logic" tries to avoid battery going over 30C to prolong life. Which is not possible at ambient 25*C or more.
And it gets very aggressive at 50*C. And this avoids going any higher.
AFAIK, even power output will be limited at very hot temps. That is mostly noticed by slower acceleration.
Max speed driving requires just 40-50kW power output so temp hardly changes top speed.
At least 40kWh Leaf will not degrade extremely fast if battery management throttles that much
Unfortunately Leaf2 doesn't have "keep battery cooler" button or "chill" button like Tesla has. But to do it manually:
Avoid heavy regen.
Avoid accelerations above 30kW
void speeds above 100km/h 60mph.
Avoid charge state below 30%.