No warning message when changing address of one customer sharing address with other cust

Summary:

When trying to amend the address for customer number 44021, I noted that the address then changed without warning for customer 44122. While we have seen instances before of customers with the same addresses having a link, we have only seen this happen at site level, and there has always been a warning that other customers will be affected. In this instance there is no warning, and the update to the other customer is instant.  Any insight into this will be highly appreciated

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