Since the dawn of time, behaviour and combat mode commanded by a group leader has not stuck with other players in multiplayer.

When you order a player into a different behaviour (Eg. Stealth) or combat mode (Eg. Hold Fire), he'll go back to what he was before after a few seconds (Because the remote player is a non-local unit).

This causes a few problems:

1. You cannot order a player unit to "Fire at will" after ordering him to "Hold fire" because he'll only briefly go to the "Hold fire" combat mode, then go back to "Fire at will".
2. If there are only players in your group, you cannot whisper or yell, because you can't make them stick in stealth or danger mode, etc. (Unless you have AI units in stealth or danger mode).

Now, one issue with making them stick could be, that you can't tell players to hold fire over and over (In case they didn't hear, or started firing).

So my proposal is to make behaviour and combat mode stick, but make subsequent orders for the same behaviour or combat mode say the command again.

Or better yet, if they're already in "Hold fire" state, and you say "Hold fire" again, the unit could say the "Do NOT fire!" phrase. Would be cool in singleplayer too.