I have been reading from other sources that it is expected a state return to be accepted/rejected before 48 hours after filing. Once it is accepted/reject it is then put in a queue to be processed. I believe that queue is what NJ State is referring to when it says to wait 4 weeks until trying to track the status of your return. This initial "accepted/rejected/pending" state is simply to show whether or not NJ has acknowledged they have added it to this queue.
If it does not update by Thursday, I'm going to give them a call and see what the hold up is.
