So, what usually happens to me, and this could be due to an option I haven't noticed or something the like, but:
I'll be controlling units by selecting them with the mouse, telling them to do something, then left-clicking to deselect, selecting another unit, giving that unit an order and... I'm still giving orders to the first unit!?
This happens especially when giving a unit an order to use a targeted ability, for some reason the de-select doesn't always go through and you have to wait a good 2-3 seconds before being able to deselect.
I became conscious of this being the case when trying to micro multiple Dire Avengers without them all being grouped together, so instead of pressing Q 3 times for grenades and spots I'd select unit 1, grenade, select spot, select unit 2, grenad- s*it.
I don't have Sticky Selection on, but somehow when I go from one unit to the next there's a kind of latency in the command input. This is compounded when you have a lot more units, say 10-15+.
On the other hand, I have not experienced this issue when using the keyboard shortcuts for control groups, when trying to reproduce the exact same thing.
Anyone else experienced this? Is it just me?