I tried [prepend note] before poly. then inside the subpatch i used [t i i] to unpack those messages. The result is i can only play the very first note. then i can see the frequency and velocity values in the subpatch but there is just no sound.
It is working with prepend midinote. Maybe you meant, why it is not working with prepend note. The difference between the note and midinote messages as I understand, is that with the latter it is memorized where each note on is sent so that a corresponding note of will arrive at the same voice nr. Then it is possible to use that note off (as is the case in your patch) to free this voice. With the note message freeing the voice happens not because of a note off but because of something else that has been provided by the programmer.