First Post. Could use some real estate help.

Sorry to be "that" guy that jumps in with a request on their first post, but I am at a loss of where to turn.

I am selling and have an offer on two parcels that abut each other that we have always farmed and been in the family for about 40 years or so purchased by my late father-in-law. Total is around 60 acres. We are are selling it, but the tax maps are showing this strange gap between them that mirrors the county line. It affects not just our property, but the neighbors as well. I pulled up the map here on FBN and it shows as a clear gap between parcels that we have always farmed as one. See the attached screenshot from FBN's map. I also attached the same image with the two parcels that we thought abutted each other outlined in yellow. Any idea what that clear area is? As I said, it continues south through seveal more properties not owned by me. I see the same line on OnX and other real estate platforms. Any insight is appreciated