Spring RTS Engine

As title says. Clean install of last spring, RAI AI with BA 6.1 mod. Game runs very shoothly, but when I select an unit or add let's say anything to build queve in factory, it generates delay. After half a second everything goes back to normal, and by that time it shows like I had a lag of 350-500ms. Installation bug or engine bug? Help.

Does that happen when you host your own game?

Ok, I will be more concrete. I host my own, single player game and I play with computer bots.

0.76b1 spring engine
mod: balanced annihilation 6.21
AI: RAI (latest release)

happens on every map (I launch from SpringSP 0.9) and when using other AI's (KAIK, AAI, NTAI)

Happens also on every game launched directly by spring.exe(e.g. COMMANDERS script)

action - selecting any unit on the map or adding item for build queve(only for factories, doesn't freeze when I tell my commander to build e.g. solar collector at x,y)
effect - game freeze for 300-500 ms depending on number of units on the battlefield

I don't remember this happening with old spring (0.5xx series).

Because I have no multiplayer experience I can't deny/say what would/could/might happen. By saying lag I meant completely software delay of application.

offtopic:
In recent spring terrain is no longer affected by artillery or it depends on map settings? I haven't played spring for longer while and missed some things.

Terrain is still very well deformed, and it's done differently depending on what kind is it. Try getting a really heavy artillery thing pounding on the ground for a bit, you should see the effect.

The engine has always used somewhat of a lazy loading approach. If you have a slow machine and click on a building icon thats never been picked before it loads the unit up which on slow computers results in a momentary freeze.

This is not something that only happens in the new springs, this is how it has always been and your remembering things through rose tinted glasses.

This has nothing to do with the AIs.

As for terrain deformation that's mod dependant. Spring didnt change here, XTA did.

Well, my comp specs are:

3,2 ghz Pentium IV
1536 RAM
ati X600 128mb graphic card

And it apparently doesn't matter whether I click it for first time, or do it over and over again. Like I said it hadn't happened before, what's funny before I upgraded my computer it had only 512 RAM and problem was non-existent with o.5xxx series. As for the AI I posted that just as additional information, I highly doubt it has anything common with bug I'm experiencing. Anyway, this is not that game ruining. Just a minor annoyance ...