The "nimble" armor modification is as follows:
Nimble armor is designed for flexibility and ease of use, although this compromises its protective qualities. Nimble armor’s maximum Dexterity bonus is increased by 2, and its armor check penalty is reduced by 1 (minimum 0).
Nimble armor’s armor bonus is reduced by 1.
However when applied to armor, the modifications do increase the DEX stat bonus by 2 and decrease AC Check by 1 - correctly. However the Drawback is currently coded to increase the AC armor bonus by 1, but it should be reduced by 1. I made a change in the .lst file that changes the Bonus from 1 to -1 (attached) - i tested with my character file and it appears to work correctly now.
I haven't ever submitted a Jira ticket for PCGEN - sorry if i did it wrong.
Pathfinder Player Companion: Adventurer’s Armory 2 defines several armor modifications captured in the aa2_equipmods.lst file.
i noticed that a character file was requested to help test, in other Jira tickets, so here is the pathfinder character file that i observed the issue with. there are 2 versions of the half plate armor - one with the nimble equipment modification and one without.