Hello,
Very strange.
It seems that when a soldier, in battlescape, put something on floor and/or take something, it will be no more possible to "affect" reaction TU to this soldier.
I can't reproduce this bug when I want. But two of my soldiers have this and I think it is from they put or take something on the floor.
It is possible to reserve TU for fight during the move but no for reaction fight.
I hope I'm clear.
.
