Why is everything going through Mangle Forward?

On my hEX v6.39.2 there are 3 dummy Mangle rules automatically created because I’m using fasttrack. There is a passthrough on each of the chains prerouting, forward, and postrouting. They all have exactly the same packet count. I thought traffic intended for the CPU (e.g. ssh connection to the CLI) did not go through the “forward” chain. The packet flow diagram also makes it look like CPU traffic would go through prerouting, input, output, and postrouting chains, but not forward chain.

Also, Mangle input and output chains have different numbers of packets, so why are prerouting and postrouting equal? What am I not understanding?

/ip firewall mangle print stats
 #    CHAIN                                                     ACTION                            BYTES         PACKETS
 0  D ;;; special dummy rule to show fasttrack counters
      prerouting                                                passthrough               4 914 009 008       6 566 080
 1    ;;; special dummy rule to show fasttrack counters
      input                                                     passthrough                   1 241 390          12 106
 2    ;;; special dummy rule to show fasttrack counters
      output                                                    passthrough                   2 953 143          10 911
 3  D ;;; special dummy rule to show fasttrack counters
      forward                                                   passthrough               4 914 009 008       6 566 080
 4  D ;;; special dummy rule to show fasttrack counters
      postrouting                                               passthrough               4 914 009 008       6 566 080