Northern Cross Fanatic with the Pummel (2) and Cleave upgrade options. Pummel works as expected if she is only engaged to one enemy. The bug comes if she is engaged to two (or more) enemies, and Pummel and Cleave activate at the same time on the first attack of the turn. When both activate on the first attack, she will attack twice, and will cleave all enemies around her twice, as expected. This should make the second basic attack of the turn 5 AP. The system even says she can attack at 5 AP, but she cannot. However, if you get her up to 8 AP, through giving her AP with Impatient, she can attack a second time. Cleave activates again, as expected. I theorize something is stacking an additional attack into the chain somewhere, even though attacks through both Pummel and Cleave should be "free." (Pummel costs 1 AP extra, of course.) Bug might also exist with Tundra Yeti, since that unit also has Pummel and Cleave, although its Pummel is a different rank. I only tested the Fanatic.