I have encountered a very strange bug that I will try to explain with my limited english.
When enemies are under the Link condition, if a creature dies and then you attack the creature who is the source of the Link condition, the creature you just killed will reappear on the battle scene, but not in the action queue. The consequence is that you cannot select that “resurrected” creature and the worse is that you cannot validate any command anymore on any creature at all (attack, diffuse, spells, …). The only solution I have found is to hit the back button on my android device or force closing the game to avoid fleeing the battle.
I don’t think this happens every time you face Linked enemies so I don’t really know why it triggers.
If you need more details, I’ll try to take notes the next time it happens. It has already happens to me a few times since 1.0.12 but I’m pretty sure it has happened before too. And I think it has happened a few times with the Taunt condition instead of the Link condition.