pg_file_settings

When I read the docs for pg_file_settings view on pg_file_settings

.... This view is helpful for checking whether planned changes in the configuration files will work, or for diagnosing a previous failure. Note that this view reports on the current contents of the files, not on what was last applied by the server. (The pg_settings view is usually sufficient to determine that.)

But the following test shows the opposite. When the parameter value is "on" for log_connections, there is no error for value, which is the expected case. But If I change the value in postgresql.conf to "dummy" then re-run the query, this time I expected the error column to show error, but again it is null, which means, I potentially apply this value to the parameter. 

Is there something I am missing?

Client and server is 16.1 from the RPM package.