The top left puzzle where you have to take three 4s onto the top shelf. It is totally unsolvable. And it is rated easy. :-(
I am 99.99% sure of this because I have solved each and every puzzle in all other packs. 1190 stars before attempting this pack. Spent 2 hours on this and tried every move sequence. Not possible at all. I can probably write a program to perform a brute force search to prove it, but I don't think it's necessary.
I will mark this down as another blunder by the development team. So much time wasted on one broken puzzle. Not impressed. :-(