NJ is one of a few states that taxes telecommuters (and has done so for years), so you must continue to file there:
https://www.journalofaccountancy.com/issues/2009/jun/20091371.html
https://www.thetaxadviser.com/issues/2010/feb/apractitionersguidetothetaxationoftelecommuting.html
http://www.koscpa.com/newsletter-article/state-tax-consequences-telecommuting/
