Problem updating customer information via API

Hi there,
I have a problem using Books API where when trying to update a customer's billing or shipping address, it will fail if I add any spaces in the fields.
For example

This will fail:

"billing_address": {
        "address": "100 My Street",
        "city": "Any Town",
        "state": "",
        "zip": "",
        "country": ""
    },

but this will work:

"billing_address": {
        "address": "100MyStreet",
        "city": "AnyTown",
        "state": "",
        "zip": "",
        "country": ""
    },

Can anyone help me with this?

Edit: This applies to any field, not just the addresses specifically.