applying hot coat several days after laminating.

So I `ve had bubbles all over after hot coating. 
I have done some wood surfboards, and I find it hard to laminate and see how your work is going when laminating over a white (no contrast!) blank.
I`m pretty sure those bubbles weren`t there before hot coating though.
I was searching on the archives trying to find what the problem could have been, and read something about applying the hot coat over a lamination that`s been done many days before ( also my case ), and getting lots of micro bubbles. 
Someone suggested that you should apply a cheater coat before the hot coat in these situations.
why is that?

could this have been the problem?

thanks in advance