You are destroying the Timer you have at the layout on layout start.
So what happens is, when you click, there's no object Timer at all.
When you check if it is NOT on layer 0 it isn't because it doesn't exist.
When you check if it IS on layer 0 , well, it isn't either, there is no timer.
In programming that would be similar to getting a null reference error, you are trying to get something that doesn't exist.