Why do I have two hits including one with a 302 redirect?

A 302 redirection appears when Piano Analytics sets server-side cookies:
If a visitor sends a hit towards our servers but no cookies are set for them, then the collection server will force a 302 redirect. This initial hit is not taken into account, as it is simply a way of asking for a third-party cookie to be set on the collection domain (most often pa-cd.com). Once the cookie has been created, a second hit is sent containing the exact same information as well as an &Rdt=On parameter. This second hit has a 200 OK status and is processed.