Tower already done

Good morning,
The tower I selected in the screenshot (link below) I completed a little while ago and have already used 3 tablets inside it. Subsequently, I made a map (the one on the right, now green) and I have just completed the tower next to it where I am currently positioned. At the moment, it won't let me place tablets in that tower but it's letting me put them back in the "Lost Tower" tower done before.
Has something happened to the server?

https://ibb.co/rfdzLV18

GGG, why aren't you fixing this and a lot more issues instead of introducing additional features?