If this wasn't a scout, then this is exactly the intended behavior. They are very, very hostile except to scouts. Poking your head into an AI planet that is high level with anything but a scout is a very dangerous thing to do, like poking your head into any enemy encampment in real life. Fear the AI. 
I definitely had a system send a guardian at me that had never seen a single non-scout ship from me. This was... maybe 10 min after capturing and having set up my 2nd system, so the system was absolutely clean.
I had been using scouts alot. Already had MkII and MkIII unlocked and flying around.
Basic defense has gotten a bit overly complex with the new version... How is a new(or even fairly experienced) player supposed to have any clue what fairly numerous different forces to keep around to be able to survive taking any system more than 1 hop out? Much less and still have other forces. The required diversity of defensive ships has gotten a bit... Wide. Particularly when you are talking about needing enough of each of these forces to take down guardians... which are no joke...
Having to have certain starships to stand a chance? Ontop of all 3 triangle ships? E..... yeaaa... Seriously? I had Mk1-3 Teleport battle stations(which have a bonus vs swarmer armor) and the crazy something like 9000 armor on that laser guardian... well... lets just say they weren't all that much help... My Mk1 frigate cap barely taking down the ONE guardian... that was being slowed by a logistics center and notably being fired on by all my telestations too(which were mk1-3 maxed).
How are we supposed to be handling the 20-30 guardians most systems have? Seriously? Even more so with the extreme diversity in what it takes to take them down individually.
Just... Expressing some concerns here. I'll manage. But...
Edit: Basically I'm saying there needs to be a basic formula for a survivable defence... and that ATM it takes [CalculusJoke]implicit differentiation[/CalculusJoke] to make any sense of it
/Edit
Also... Guardian responsiveness to raids... I suspect needs alot of ah... "fine tuning"
But I imagine you already knew that. Haven't played around with the new version too much, so not sure what my opinion is of how much so...
Mmm and Are guardians REALLY supposed to be normal-ship speed? Seems a bit odd for something that is so super-powerful and the AI step-in for turrets. I know them being mobile is essential to their counter-attacking and being more effective defenders... but...
That all said. Loving the zooming.
In a more technical note, the game is having one issue Ill toss onto the bugtracker. When in windowed mode it is refusing to be 1920x1080 on my 1920x1080 screen unless I have another monitor on extend(in whcih case it goes to... 1920x1050 automatically I think...). Don't mind the height atm, though if my start bar was on another screen I would.
Yes, I know the window would go slightly ofscreen due to borders if it were actually 1920x1080... I put the borders just off the sides. Makes something CLOSE to the old days to some degree... Basically its disobeying the set resolution if it is equal to screen res, and going down one standard size in that dimension if so. Which is highly undesirable.
