When you use "System-> Create", this creates an instance of your object, which inherits all behaviors, instance variables, effects etc. of the object. So if your block sprite has Physics behavior, all instances of this block will also have this behavior.
When a new instance is created, all its properties are copied from the very first instance of this object which you placed on the layout in the editor. So if your first block instance has "Physics Initial State=Disabled", then all instances created in runtime will also have Physics behavior disabled, and you'll need to enable it with events.