In the screen data where you place a 0 for the secret sound to be off then save as 2.10, the rule doesn't carry over into 2.10. You open the quest in 2.10, but the rule isn't checked.
And it works the other way around. Rule checked in 2.10, open in 718, save as 2.10, open in 2.10 or 718 and the rule is no longer checked or a 0.
[718] No secret sound rule not saving as 2.10
Save as 2.10 was a stopgap feature that will be removed in 2.50, and hasn't been kept up-to-date with any kind of rigor.