That was something I noticed while testing too. I tried to fix it by having a random spawning array then a continuous array that would spawn the next note then restart. I think it helped a lot but yeah, if you miss it then you gotta hope the rng is on your side lol. Thank you for playing!!
Not sure how you could do this, but could you increase the probability of the note you need to spawn, maybe 2 of the note you need in the spawning array?