Sealing Marijuana ACD Cases Eairly Criminal Records, Expungement

I was arrested last Nov. for possession of a Marijuana Joint in the state of New york. I am a first time offender and I was issued an ACD. I was told i needed to stay out of trouble for 1 year and everything would be dismissed and sealed in a year. I have now moved to another state and I am trying to find work, but my case is showing up on my background check. I recently went back to court to have my case sealed earlyer than the years time, and the judge granted that it would be sealed immediately.

QUESTION: Is there any possible way that my ACD case will still show up on pre-employment background checks, even tho the juge granted it to be sealed right away? And how long does somthing like this take effect?