Spawn System Problems

Can anyone suggest anything to help prevent the spawns "sticking" as more of them come in?

I'm using a standard system, with one trigger to create the units, and another that detects when a unit enters the spawning region and orders them to attack move to the goal.

You mean like you only can have n units on map? Units of type in unit group (owned by player x) < n

Tried it.

Um...what is wrong then...? Don't get what you are trying to do...

I guess what he is talking about is that when new units try to spawn and don't find where to spawn, they appear right on top of old units and create massive lag.

Actually, what I was saying is that when the number of units in a map gets too large, they'll keep stopping, rather than moving constantly to the goal as I wanted.
No problem though; it turned out that simply reducing the unit cap still further was enough to fix it. I'd tried before, but the number was still set too high, I guess...

Can be fixed by ignoring the AI guard position before you order them to move.