Thanks for the feedback, did you reset the letters using Duck before completing the level?
For the "boy-girl" level I remember that I did because the offset letters got me. For the "is-are" level, I don't remember.
I think the bug then is that the reset doesn't reset the true values for letters already put into place. So you only have to get each letter tile into place once. I'll change it, I left it like that so players didn't have to do everything again.
Issue fixed, I added some resets to the variables. Now if the duck or balloon is interacted with, the letters are reset and you have to push all the letters into place to progress.