Altium PCB Parameter Live Updating Issue
For Altium 17, in your PCB, when you up the View Configurations and select View Options, you'll see an option that says Convert Special Strings.

See: Documentation for more information.

I cannot seem to find it Altium 18, so I think it might always be enabled.

According to the their documentation, it is always enabled.


  The Convert Special Strings option has been removed since the string
  is always displayed; if null, then the parameter name is displayed.


Source: Link