I have had this happen many times now in different versions of the game. While playing in game, I will have several units decide to autogroup and clicking on any one of them will select the whole group. Once this happens, all commands given will also be as if I held the SHIFT key and gave multiple commands. If I hit ESC and tell units to stop, It doesn't matter. Any commands given to any one of the units, once they've joined the group, will send all the units marching the path of ALL the commands to move. Only death of the units seems to stop this and I have had my entire force do this. In essence I lose control of the units.
I have all the currents drivers and have reinstalled the game a few times now. For some reason this continues to happen. I know it sounds odd but it happens, especially in multiplayer games. Anyone else have this problem??