It's really hard to tell exactly what's going on -- but...

http is port 80, and https is port 443 -- this may explain some things if all you're doing is monitoring port 80 (though I've never used ethereal myself).

If you don't want LWP to auto-follow redirects, change the requests_redirectable line to

requests_redirectable => []
[download]

If you really do want to auto-follow redirects but it's not going to the same page, there may be some user-agent-based filtering happening on the server side (it's really hard to tell without seeing the actually output)

Firefox's LiveHTTPHeades plugin is a really great way to see the request/response flow -- it may be a little easier to see what's going on with it instead.