isAA values: just sets isAAmovement, isAAforCombatOnly, isAAforBombingThisUnitOnly, isAAforFlyOverOnly, isInfrastructure, and isRocket to true. (allows a unit to shoot at air units before combat starts and not participate in the rest of combat, have certain movement restrictions, and be capturable)
Perhaps removing that option name and setting the values seperately will solve it. You already have some set i see.
This is a bug and I seem to remember (not sure) that infrastructures were able to retreat in previous TA versions (in Feudal Japan), while I tested now they can't.
So my guess is that some late changes made them unable to do so.
I confirm this bug exists and it is influential for at least the Feudal Japan map, where "Horse" can't retreat (while it should be able to).
I'm almost sure that infrastructures are meant to be possibly sent or used in normal combat, and there are maps that do it (for example, the Fort of Rome Total War).
So, this is a bug that it is bugging off at least 1 existent repository map.
I suggest you make a bug report about it, preferably with a savegame of Feudal Japan showing the bug off.
p.s.: I also believe that "air" "infrastructure" should not be captured nor destroyed in a failed attack (because they are not really in the attacked territory, but flying over it).
p.p.s.: Up until the bug gets saned, you can easily get around it by hacking. The reason why they don't retreat is that infrastructures not anymore relevant for combat after an eventual first round only AA shot are removed as active participants in the battle. So, you can have them able to retreat by giving them anything that will make the engine keep them for the whole duration of the battle; for example, giving a 0 or whatever negative support attachment to itself (you don't need to give an attack value, as just having a support ability will keep the infrastructure in the battle). Of course, as this being a hack, it would be preferable that some developer sanes the bug, instead (and if the bug gets saned, you should remove this hack, if you decide to use it, meanwhile).
Ahhhh. I was positive isInfrastructure wasn't the problem, because I have other units that are isInfrastructure or isFactory and they have no problem retreating. But they also have support attachments (not as a hack, but because they're actually support units).