The 2nd law’s edict that systems thermalize is regularly violated. Some quantum systems thermalize; others don’t.
One thermalization violation occurs when cooling gas, substantiating Maxwell’s demon: an 1871 thought experiment by Scottish physicist James Clerk Maxwell, who hypothesized a way to decrease entropy by a method now proven.
In nanoclusters of jostling atoms, some clusters ricochet off each other faster than their collision speed. This violates the 2nd law.
On average, the rebound is less energetic than the collision. Fast bouncers appear 5% of the time; enough to violate the law while leaving it an adequate approximation.
Experiments with entangled atoms have shown that heat may flow from cold to hot, contrary to the 2nd law. This may not be a strict violation of that law, which presumes no correlations between particles – an unrealistic assumption, however commonly it may appear to apply.