redirect 302 then redirect 304

I have multiple instances where I need use redirect_to in a controller,
and two of them exhibit the problem that I'm describing (the two that
update the record on which their acting)

On my development server (mac, webrick) I see two redirects, and the
client gets data back - - [06/Jun/2008:13:32:16 CDT] "POST /events/49 HTTP/1.1" 302
97 -> /events/49 - - [06/Jun/2008:13:32:16 CDT] "GET /events/49 HTTP/1.1" 304 0 -> /events/49

On my deployment server (linux, apache) (running in dev and production
modes -- both were tested), I see a redirect to the same id with status
302 only, and the fcgi instance returns an error (nothing in log
indicating it).

What would cause the second (304) redirect?

Thank you,