Taunt and Cavalry free maneuver
How does it work?
There is a lot to discuss and a lot to argue, it's all in the interpretation of the triggers "When a unit activates" and "At the start of a unit's activation".
If the conditions that triggers "When a unit activates" and "At the start of a unit's activation" are two different conditions, and the earlier condition to trigger is "When a unit activates", then, the taunting unit would have to declare and use taunt on the cav unit, then if the cavalry unit could attack or charge the taunting unit, but would then use the free maneuver to lose LOS or range on the taunting unit, the cav would still get the tokens from taunt, since the action it took was not to charge or attack (and it could).
If the condition "At the start of a unit's activation" is earlier then "When a unit activates", then the cavalry unit could use the free maneuver to lose LOS or range on the taunting unit, then the taunting unit could declare his taunt ability.
It depends. There is not a sure answer, do as you think it's best. Let's hope for a FAQ.