Massachusetts Nonresident Return

I am preparing both my and my husband’s tax return.  We file separately for student loan reasons.  He only works in MA but turbo tax is coming up with a number for income earned outside of MA.  This number matches the difference between is federal wages (box 1) and his state wages (box 16).  However, he does not work anywhere else.  Should I delete it and put 0?  He received a corrected W2. I ran a joint return just to see the difference and turbo tax stated we had “0” for income outside of MA.