been a while since I played so the little info I have to offer might be out of date... but keep in mind that once the dyson starts to spew out gatlings, all it's surrounding AI planets will be on alert. When you remove your scout from the dyson world, they will STOP spewing out gatlings until you put a scout back there again (or if you go and liberate it of course).
This is intended behavior. It used to be that the dyson would start spewing out gatlings the second you started a new game, which would cause it's surrounding AI worlds to be on permanent alert from the get-go. This could cause the alerted AI worlds to build up forces so much that over time they would start leaking into other worlds. This could potentially be game breaking.
I once made a 9/9 crosshatch AAR where this occurred. 8 AI planets (including 1 or several mk IV ones if I remember correctly) were on alert at all times. The dyson gatlings couldn't keep up at all and at some point I had a steady stream of mk III/Mk IV ships pouring into each of the few planets I had. After that I pretty much begged Keith to change it and thankfully he did. The link below is my second crosshatch AAR before the fix was made and I won, all because I turned off the dyson sphere. This was all before scaling was introduced into the game. All minor factions could only be turned on or off (on being equal to 4/10 as it is today).
Now a player ship (any ship really) has to be on the dyson world in order for it to start spewing out gatlings. Remove your ship and the gatling vomiting stops (and the alerts too).
As for the guard posts... guard posts used to be incredibly weak and posed no threat to the dysons. Since guard posts could help decide how many reinforcements a planet would get which each 'tick', the devs felt it wouldn't be right to just let the dyson gatlings waltz all over them and make your life even easier (I believe it was something like this at least). That's why they can't shoot at guard posts. I believe that line of thinking is still correct, so I suggest you turn up the scaling
I don't think the gatlings should be allowed to shoot at the guard posts or have guard post immunity. Total destruction for simply putting a scout on the dyson world is too cheesy. I've always believed the gatlings are intended for the defense of your empire once you've liberated them. Let them patrol your planets and take out threat fleets here and there, like zombies.
But like I said, it's been ages so I'm not sure how valid my points are. Hope I've been of some help though =)
