Tower Bug (Tower was used msg)

There is a bug when I completed a tower with 3 slots for influence - when put the tablets in and pressed the influence button it says "tower was used" even though it is the first time and never been used.

This started to happen when I completed the tower map and died afterwards. One of the towers tablet slots just disappeared and then I tried to complete other towers then all the influence buttons started not working with the same "tower was used" error.
Hope you guys fix this bug.
Thanks.