Quote @themasterchao from their YouTube Comment:

I love how Solanum's song has a syncopated rhythm compared to the other traveler's parts. The notes don't fall on the beat, separating them from the other instruments. It really feels like an alien addition to the song; Solanum imparting her own culture into it that's completely different from yours. But at the end of the loop, it unites with the main melody, just like both cultures came together in the end to make this possible.

References

• https://www.youtube.com/watch?v=X9J42W2pVs8