Two things i noticed

[CountArach]

Alright I'm not sure of this, but I think the second on is because the infantry is supposed to just get rid of skirmishers, which is accomplished much easier when spread out.

As to the Akontistai, this is because there were a lot of them and they were relatively easy to equip and field.

[Teleklos Archelaou]

It's not a loose formation (as in they don't have the loose vs. tight formation selected) it's just that they aren't group tightly together to begin with. I don't know the reason why though - just wanted to clarify that as I just saw them.

[galathas]

In any case it does make the Taxeis Triballi extremly vunerable to cavalry and not very effective in melee against any infatry unit. This just doesnt seem right for an assault infantry unit.

[Teleklos Archelaou]

I've asked on the development forum and we'll see if it was intentional or a mistake. Good point though.

[Fondor_Yards]

I think the ai does that because they think it's a missile unit, it does the same thing for peltasts sometimes.