Oracle UTL_HTTP gzip response with non-200 status

Question

I have a very strange problem with UTL_HTTP. I'm calling an API that can return a gzip encoded response. This is handled correctly when the service returns a 200 status code. However, when I try using get_text or get_raw on the response when the status is not 200, I get the raw gzip data. I've verified this by using rawtohex to examine the response and it has the initial hex value of 1F8B i.e. the magic number for a gzip file.

 declare
  l_raw raw(32767);
 BEGIN
   LOOP
     UTL_HTTP.read_raw (l_UtlResp, l_raw, 32767);
     dbms_output.put_line (rawtohex(l_raw));
   END LOOP;
   UTL_HTTP.end_response (l_UtlResp);

 EXCEPTION
   WHEN UTL_HTTP.end_of_body THEN  
     null;

   WHEN UTL_HTTP.transfer_timeout THEN
   WHEN OTHERS THEN
     RAISE;
 END;

Outputs a string like

1F8B08000000000000006D504D4BC43010F...

I've exhausted my Google search skill trying to find a solution for this.