It seems that the sentry's hp is bugged. The sentry's hp doesn't represent the sentry's physical health. When you shoot the sentry once (even with just 1 pistol shot), the game thinks it's dead even though it's still alive and shooting. Because of this, the enemy will attack it once then never again.
Is this a case for other players too?

Its working in my game i dunno man.

I've disabled every addon besides this one and it's still the same situation. Maybe it's something wrong with the workshop version? Try and get a tester friend to test the addon out from downloading here.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2381711639

It's not compatible with iNPC by xyzzy, turret starts to shoot every NPC no matter what (Target Filter doesnt work)

Sentry shoots members of set faction. Filtering many npcs of the faction INDIVIDUALLY works, but it's boring and time consuming

Addition: It shoots all combine npcs with no exceptions, doesnt touch resistance if set to this faction, but kills VJBase npcs