New Jersey allows employers to determine your work location and your employer has decided you are a New Jersey employee. As a result, you have to pay tax to NJ, as if you commuted to an office in the Garden State every workday.
New York will give you a credit for tax paid to NJ.
The NJ Division of Taxation says "New Jersey sourcing rules dictate that income is sourced based on where the service or employment is performed based on a day’s method of allocation. However, during the temporary period of the COVID-19 pandemic, wage income will continue to be sourced as determined by the employer in accordance with the employer’s jurisdiction." Telecommuter COVID-19 Employer and Employee FAQ.
If you want this changed, you'll have to speak with your employer.
