Edit: I have 6 of these.
This is what it looks like on my map.....AND I now have 32 coin pits.
That also has happened to me about 2 or 3 times in the past month but changed just a couple hours later.I once saw a brown city in the middle of my neighborhood with all green around it. It looked so strange, but it went away and was replaced with a new player in a day or two. Good luck!