Magento 2 SOAP API Question

Question

I am using Postman to test send data to different websites e.g

I have 2 websites each has its own domain e.g onoe website one store and one store view per domain.

e.g

1- http://test.com have:

default website -> default store -> default store view

2- http://test.co.uk

website two -> store two -> store view two 

this my setup to send data to website two

POST = http://test.com/soap/store_view_two_code?services=catalogProductRepositoryV1

XML request=

  <?xml version="1.0" encoding="UTF-8"?>
 <soap:Envelope xmlns:def="http://test.com/soap/store_view_two_code? 
services=catalogProductRepositoryV1" 
xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
  <soap:Body>
   <def:catalogProductRepositoryV1SaveRequest> 
    <product>
      <sku>000123-sku</sku> 
      <price>99.00</price>
    </product>
   </def:catalogProductRepositoryV1SaveRequest>
  </soap:Body>
 </soap:Envelope>

XML response=

<?xml version="1.0" encoding="UTF-8"?>
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
    <env:Body>
        <env:Fault>
            <env:Code>
                <env:Value>rpc:ProcedureNotPresent</env:Value>
            </env:Code>
            <env:Reason>
                <env:Text>Procedure not present</env:Text>
            </env:Reason>
        </env:Fault>
    </env:Body>
</env:Envelope>

Now that tell me that def:catalogProductRepositoryV1SaveRequest isn't defined in the store_view_two_code

But if I change the the url for the request in xmlns like this:

...
<soap:Envelope xmlns:def="http://test.co.uk/soap/store_view_two_code? 
services=catalogProductRepositoryV1" 
xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
...

Note: I've just just replaced the test.com to test.co.uk and that gives success response. Can someone tell me if this is normal behaviour why do I need to specify the the domain for the second url in the request to get success While the POST URL never needs changing?

Here is some ref: https://github.com/magento/magento2/issues/14626

Thanks in advance.