Because of weightings around other things you aren't going to get a 1:1 50% of input code used node so it uses node 50% of the time. There's enough randomness

Because of weightings around other things you aren't going to get a 1:1 50% of input code used node so it uses node 50% of the time. There's enough randomness and other stolen content to (in theory) bias it towards weird outputs/choices