They detail helium preloading of the COPVs, which has some of us scratching our heads.

… the Falcon 9 composite overwrap pressure vessels, known as COPVs, will be loaded with helium and verified to be in a stable configuration prior to astronaut arrival at the launch pad. The astronauts then will board the spacecraft about two hours before launch, when the launch system is in a quiescent state. After the ground crews depart the launch pad, the launch escape systems will be activated approximately 38 minutes before liftoff, just before fueling begins. SpaceX launch controllers then will begin loading rocket grade kerosene and densified liquid oxygen approximately 35 minutes before launch.

The COPVs are placed in the Liquid Oxygen tank to increase their capacity. My best interpretation is that they will precharge the COPVs to operational pressure with ambient temperature helium gas, and then complete the helium load at constant pressure as the LOX cools the COPVs, thus avoiding the conditions which led to the AMOS-6 loss.