Super, always pleased to learn new stuff.

So what is happening is that the CGI.pm is sending headers to Apache to send back to the client. However Apache notices that the status is 200 and that there is a Location header and decides to issue a new request through itself for this location. So until the new location's data is grabbed and is ready to go back nothing is sent to the client making this an internal, as opposed to external, redirect.

So without forcing a status of 200 CGI.pm redirect would send back a status of 302 (Moved Temporarily) which Apache would send on to the brower to deal with.

I believe I am clear an this now, thanks for the clarification.