[Solved] How to determine support in combat
Is support determined at the beginning of the combat phase or at the time of each unit action?
Or put another way, can a unit that gets a breakthrough lose its support in the next combat, and therefore put itself in greater danger of route.
-Yahoo Group, 5/12/16
At the time of each result is when support is determined, yes. That is true of all (?) such things (I believe).
And yes, it means that Units become more exposed to danger if they are too successful.