what's happening is that the note randomness uses `rnd` which isn't affected by the seed. while the note duration uses `trandom` which is. i don't know much about rnd or how it works, but if you use `random(0, 1)` in its place (because rnd is unipolar) and use different seeds it will be affecting both the duration and notes

oh there's even an opcode called `rndseed` which to `rnd` is like `seed` to the random family

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