Partial resident tax return in NJ

My wife and I filed the NJ 2020 tax return as partial residents. Because my wife worked in NJ and CA in 2020. I was working in CA only. The turbotax helped us filed both NJ-1040 and NJ-1040NR.

 

Today, I just received the notice from NJ regarding my non-resident return, which has amount due. It asks me to pay the amount due. However, my resident return has the refund, which is more than the amount due on non-resident return. 

 

I am wondering if the NJ tax division handles the resident return and non-resident return separately? Will I receive the refund in a different mail? Thanks for your help in advance.