zarr copy of an array creates chunks of default missing values

[alonbl]

Hi,
I found out that when I copy one array to another, the destination array contains chunks that do not exist on source, these are chunks contianing the missing value (for example zero).
Is this intentional? Can zarr be aware of the missing value so that a chunk that is full of the misisng value will not be stored?
I could not find such an option but maybe I overlooked.
Thanks,