Also, please, provide repro missions only with vanilla content.

Try to spawn 15 man in random places, but as one squad, click on their icon (Alpha-X-X) , change their behavior to "open fire, keep formation", fomration "line" (also try with formation "file") and set them in formation, you should see them moved into formation now, but sometimes with 2 man in one place, which lead into serious problems on mission i made (they start to move since mission start, which i was trying to avoid)

Second is not necessary a bug, but its produced somehow, and i wanna some of you take a look. In formation "line" or "file" all squad members should stand in line behind thhe commander (behind his back). Somehow after mission starts, they move to diferent formation, in more precise - ""ECH. RIGHT". I dont know what produce the issue, beacuse i have checked everything twice, and there is only one squad doing such thing, seems without reason. Arma on standard gameplay produce such situation very often to me (most of features simply work bad, or dont work at all). I know i may be fault of bugs, but mod developers dont allow me to report bug to them. Most of their explainations are "arma bug, ask BI".

Are you moving the guys into formation by hand?

No, you got there option, after you click the icon of squad in editor, right click, (przekształć) in english it would be transform or something, and "move into squad". I use Polish lenguage, so pardon if it sound diferent in english.

No need to apologize, I just wanted to know whether you used this option.

Unfortunately I was unable to reproduce it, followed the steps with the 15 units, grouped them, moved them to formation File than started the mission. Everyone was in File, no guys standing in the same place.

Somehow after mission starts, they move to diferent formation, in more precise - ""ECH. RIGHT".

Is it possible that you have this formation set in their waypoint? This way they would spawn in File but since the waypoint dictates them otherwise, they would move into the Echelon Right formation.

I goona try now, byt if you grupped them into formation, there was 15 man standing in the line? No 2 units in one place?

No mods, and reproduced issue on profilling branch :

Also i dont know what trigger this fomration change, but i checked and everywhere formation is column (in the repro mission). I'm gonna made second mission using vanilla only.

As i suspected, in vanilla there is exacly same issue. All infantry should wait till tanks will drive out of bese, then move, but it work wront totally.

First - last tank is moving - its beacuse editor is moving units into formation in wrong places (!) - this tank start moving to find its place in formation, even after i used formation option "move into formation".

Second - All infantry will move like insects in this base, after i used "move into formation" in editor. Try this on yourself, and check if everything is marked well.

Did you by any chance test this on Development branch? I have not observed units spawning there.

Last tank moving - I observed tanks moving, not specifically the last one, but I tried to use Move into Formation on all the units and most of them were moved a little bit, including non-leader tanks.

Infantry - they indeed started moving but that is not a problem of them being set in incorrect formation by the editor rather than them keeping the formation. In FILE they are supposed to stand behind the leader, if the leader turns left, so does the whole formation, in Aware he will most likely turn as Aware means they are expecting trouble.
I was able to make them stand in the File formation by simply changing their behavior to Safe instead of Aware (of course their next waypoint would have to react to that and would need to change their behavior and so on if desired).

Also I would strongly recommend to put some timer on the Second tank group trigger or to make it bigger so it really does cover the whole base, in most cases, tanks started moving and that immediately triggered the infnantry waypoints. Tanks then ended up being hold up by the huge infantry swarm and sometimes there were, let's say accidents, with guys running under the tanks and so on :D

So first - i use only profiling branch,

Second - last tank is moving for unknown reason - i set him into formation by editor option in "transform" section.

Tanks are in 2 groups. Each of them contain 2 tanks. Mission is made in that manner, that first 2 tanks move as mission start - out of base, as they reach trigger behind the bridge, second group of tanks should move, Then second trigger is placed, and activation of it is setted by 2nd group of tanks leaving the trigger place - then infantry should move.

Infatry should stand behind leader in line also (so here is first bug - editor is not palcing units in formation properly - same with tanks - last tank should not move).

Does behavior change helping - i didnt tested it, but in AWARE it should also work. As you can see, all comanders have waypoints straight in front of them, so there is no way they could face the back in other way, than i want. Somehow, all AI in formation are moving to the right side of sommander once the mission start.

i didnt tested it, but in AWARE it should also work. As you can see, all comanders have waypoints straight in front of them, so there is no way they could face the back in other way, than i want.

Yup but they are in a Wait and Aware so they are positioning themselves as if there was an immediate threat present, so that's why they are turning, if you do not want them to move at all for that moment and still be in Aware, you will need to disable the movement for them, changing their behavior in Aware so they do not turn in other directions and so on would probably solve this problem, but would destroy Aware state in overall.

Thanks a bunch with this behaviors.

But still there is wrong formation positioning in editor.