why do some levels not work on app and only on pc?

Paul-3

on level 1452 it was impossible to clear the silver wrap before the whole level filled up and level 1475 the flying saucers got rid of the liquorice instead of counting it. on the pc it was easy to do in one go

StuckInATree

Since they are different version of the game it's always possible for there to be discrepancy's between them. It's been seen before that a certain level is easier to complete on PC compared to Mobile and same vice versa, I've not seen this one myself though and since it's in the latest added levels it's possible it's an error.