Nj/NY taxes on Turbo tax

I live in NY State and worked in NJ for 2 months last year. They witheld taxes for both states which is expected.  When I do my taxes on Turbo tax, I input that W2 and the taxes came up correclty for both states.  When I now add my other W2s (for work solely in NY State) TurboTax changes the amount tue for NJ. It has gone from positive to negative.  How do I correct this?