Config will broke some object inheritance.

Updating base class House->, by rnc_misc/fortress_01/config.bin/CfgVehicles/House_F/ (original (a3\structures_f\config.bin - no unload))

Updating base class House_F->, by rnc_apartments/variant1/15x15l/config.bin/CfgVehicles/House_Small_F/ (original (a3\structures_f\config.bin - no unload))

Conflicting addon rnc_apartments_variant2 in 'rnc_misc\vanilla_overlays\', previous definition in 'rnc_apartments\variant2\'

Those using same cfgPatch class. should be change.

to fix:
CfgPatches rnc_modular_fortress:

class CfgVehicles
{
class House; //add this
class House_F: House //and this
{
class Eventhandlers;
};
class rnc_fortress_base: House_F
{...

~~~~~~~~

CfgPatches rnc_apartments_variant1_15x15L:

class CfgVehicles
{
class House_F; //add this
class House_Small_F: House_F //and this
{
class Eventhandlers;
class DestructionEffects;
};
class rnc_house_base: House_Small_F
{...

~~~~~~~~

also change rnc_main
requiredAddons[] = {"A3_Structures_F_Mil"}; // it's not incl. apex/enoch(contact) buildings. possibly error happening.
should be change to
requiredAddons[] = { "A3_Data_F_Decade_Loadorder" }; // this require all a3 vanilla configs for load.
for better loading organization.