Don’t know if you got an answer, but I’ll try to explain what this is referring to:
Let’s say that you had a pattern on DN1 that had voice stealing. Since you now have twice the amount of voices on DNII, there might not be voice stealing anymore, so the pattern could sound slightly different because of that.
You can actually fix it by locking 8 voices to an unused track, so that only 8 voices are left to be used by the rest of the tracks.
EDIT: Also, this is true, and could affect the pattern more than what I have described above: