One way to reproduce the problem:

• Create a host with a DNS interface containing a {HOST.NAME} macro in the DNS field;
  - Create an item that uses that interface;
  - Add the {HOST.DNS} macro to the key of the item.
  
  The macro should resolve into the name of the host, but it will be resolved into "{HOST.NAME}

  ". The problem may exist in other places as well.

Related to ZBX-7137.