Magento 2.1 wrongly allows to skip the shipping address selection during checkout

Issues
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1

Title : Able to move forward without shipping address in checkout

Preconditions ;

  1. Magento CE 2.1 without sample data is installed.
  2. Customer is Login
  3. Customer have address

How to generate issue:
Add any product into cart and then go to checkout, and now unselect address from selected address and click on next button.

2

It is a long-term Magento 2 issue, not only in Magento 2.1.