Exactly as Laradon states it
Originally Posted by Laradon
the greencloud is the elven formation change. It tends to always make problems, sometimes they stop attacking after formationchange, sometimes they get stuck in it and the cloud around the units doesnt disappear etc. I wont even dare to use a formationchange in pvp, because if that bug happens the enemy can kill all those units and they wont attack. If someone in Help tells me his Elf units stoped attacking, I always ask if he did a formationchange before that. And thats always the case.
. I have encountered that bug too many times, precisely as Laradon
describes the situation, and like him, I do not dare attempt an Elven formation change (to Wind Stance) in circumstances when it could lead to disaster -- notably because of unresponsive Rangers, caught in their green cloud.