Experienced this myself, I was really confused at first when I was taking over an old claim after I had destroyed the stake that the claim still remained there but I think it's just a visual bug. Should you try and extend your own claim over it the older claim would disappear or if you leave and come back later it'll probably be gone.
Most likely just an update thing. Try relogging/waiting a while.
"The psychological trials of dwellers in the last times will be equal to the physical trials of the martyrs. In order to face these trials we must be living in a different world."