State tax filing

Hi

As a follow up on my 1st and original question, my employer has intentionally specified my State of Employment on ADP records (NJ) to to match up with my Home State of remote location (NJ). So for the 40% days worked in NY office, can you explain the reason (helpful if you can provide the relevant tax law passage) why I can't look to NJ as my source of wages? I just want to better understand this, as there must be a regulatory/tax compliance reason for my employer to want to match the State to NJ. Thank you