In a multi-map campaign, 7 maps for example, after transiting from map 6 to map 7 (could happen earlier), suddenly NPCs has almost 100% accuracy like the perfert proficiency, noticeable stronger bullet push force, and some NPCs like striders, gunships and hunter-choppers can shoot through walls with reduced damage (looks identical to the ARC9's ammo penetration). NPCs use only vanilla weapons.

(1) Issue stops when ARC9 weapons are disabled and all other addons UNCHANGED. No issues if Only ARC9 base is enabled. And I don't use any NPC AI addons.

(2) I have tried gunsmith reloaded and MW2019 weapons, the issue occurs in both cases. The issue doesn't appears to be related to specific ARC9 weapon packs.

(3) Issue only happens after level transitions. No issues if I load map 7 directly from gmod main menu. So it is not the map that changes the difficulty or npc abilities.