It appears when enemy units are stacked and you kill the first stack any proceeding stack of enemies will just show a blank tile with a number above it. As you can see in the picture the tile is blank except for the number 2. What is wrong with this is I already killed one stack so there isn’t “2” left and the tile is missing the mob graphic:
Fighting 3 or more stacks of mobs:
I move unit next to a 3 stack mob which ended my turn and then the 3 stack enemy unit attacked me. I killed the first 2 stacks but somehow the 3rd stack end up on my tile. I am assuming this is because I only have 2 movement points so even thou the enemy initiated the attack it could only attack me 2 times (Personally I feel this is wrong; if the enemy initiated attack than I have to fight however many stacks there are) As you can see in the picture (the red 3) I couldn’t do any with that stack on top of me plus I had no movement points so I had to end the turn. When I did that somehow the last enemy unit moved behind me automatically.