PA and NJ have tax reciprocity for W2 salary/wages. That means your W2 income from NJ is taxable only by your home state of PA.
If NJ taxes were mistakenly withheld from your pay, you'll have to file a non-resident NJ tax return on which you allocate zero income to NJ in order to have those taxes refunded. (PA Schedule G would not apply unless you were a dual resident of both states.)
If you haven't already done so, you should submit NJ Form NJ-165 to your NJ employer.
https://www.state.nj.us/treasury/taxation/pdf/current/nj165.pdf
Filing Form NJ-165 should result in your employer withholding PA taxes only.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
