The zombie suffers freeze damage before becoming the frozen zombie.

If you insert a normal zombie into the soft snow, the expected result would be for the zombie to start shivering and, within seconds, transform into a frozen zombie, just like a skeleton does. However, when the zombie comes into contact with the soft snow, it behaves like a living mob, suffering freezing damage from the cold, just like the player, while the drowned and the wanderer do not suffer damage when entering these adaptive transitions.