Maps rendering blank when exploring

When I updated to 18w20c today, I knocked a map off of my wall and it immediately became unexplored. When making a brand new map and exploring the same area, it is still the same.

 

Screenshot description:

On my mapwall. I removed and replaced it immediately. It looked like this:

 

Holding the old map

 

Holding the new map

Holding the map surface side, showing some local terrain