Again, I had this exact same problem: My full year NM resident client has rental property in North Dakota. I filed 2020 New Mexico PIT-1 with Line 20 credit for taxes paid to other state (Proseries rep insisted this was okay) even though I knew I should use the PIT-B. And sure enough I got the NM Tax & Rev letter stating that the PIT-B Allocation form must be used and they reduced my client's refund.  I am still trying to amend the 2020 PIT-1 with the inclusion of the PIT-B in order to get my client's full refund...I've had to override things to get it to work. Good thing (is there any good thing in this situation?) is I'm snail mailing the amended in so overrides won't matter. But it rubs me the wrong way to have to do it like this...so messy and time consuming!

And now here I am again for 2021 having the same infuriating problem! Proseries needs to fix New Mexico software already!!!!!