Steam Workshop Scenario - No 3rd party error

I've finally wrangled the AI on the NEC into submission and was attempting to upload a new GG-1 scenario for the NEC and it's being rejected due to third party software. I've gone through and scrubbed the assets both by hand and with railtools, and at this point I'm scratching my head as to what is triggering it. I've tried to limit the scenario to only using the NEC, Horseshoe Curve, GG-1, and Cajon Pass for DLC.
The only other thing I can think of is that it's kvetching over some of the 3rd party stuff that may live in the Kuju directory, but I've uploaded several other scenarios for Horseshoe Curve without an issue.
This is the asset list from rwtools
Rolling Stock Used in this Scenario:- Tile X Z
Kuju\RailSimulatorUS\railvehicles\freight\autorackcar\def2\wagon\auto_rack_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\boxcar\def2\wagon\box_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\boxcar\default\wagon\box_car.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\cementhopper\def2\wagon\cement_hopper_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\cementhopper\default\wagon\cement_hopper.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\coalhopper\def2\wagon\coal_hopper_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\coilsteelcar\def2\wagon\coil_steel_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\coilsteelcar\default\wagon\coil_steel_car.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\covered_hopper\def2\wagon\covered_hopper_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\covered_hopper\default\wagon\covered_hopper.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\doublestackcar\def2\wagon\double_stack_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\refridgeratorcar\def2\wagon\refrigerator_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\refridgeratorcar\default\wagon\refrigerator_car.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\tankcar\def2\wagon\tank_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\tankcar\default\wagon\tank_car.bin Default Stock
RSC\GG1Pack01\railvehicles\electric\gg1\prr_dgle\engine\gg1_engine.bin
RSC\HorseshoeCurve\railvehicles\diesel\f7\default\engine\f7a_default.bin
RSC\HorseshoeCurve\railvehicles\diesel\f7\default\engine\f7b_default.bin
RSC\HorseshoeCurve\railvehicles\diesel\gp7\default\engine\gp7_default.bin
RSC\HorseshoeCurve\railvehicles\freight\boxcar_x29\default\boxcar_x29.bin
RSC\HorseshoeCurve\railvehicles\freight\flatcar\default\flatcar_40ft_crates.bin
RSC\HorseshoeCurve\railvehicles\freight\hopper_h21a\default\hopper_h21a.bin
RSC\NorthEastCorridor\railvehicles\electric\aem7\default\engine\aem-7 engine.bin
RSC\NorthEastCorridor\railvehicles\passenger\amfleet\amcafe\amcafe.bin
RSC\NorthEastCorridor\railvehicles\passenger\amfleet\amcoach\amcoach.bin
The only other thing I can think of is that it's kvetching over some of the 3rd party stuff that may live in the Kuju directory, but I've uploaded several other scenarios for Horseshoe Curve without an issue.
This is the asset list from rwtools
Rolling Stock Used in this Scenario:- Tile X Z
Kuju\RailSimulatorUS\railvehicles\freight\autorackcar\def2\wagon\auto_rack_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\boxcar\def2\wagon\box_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\boxcar\default\wagon\box_car.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\cementhopper\def2\wagon\cement_hopper_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\cementhopper\default\wagon\cement_hopper.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\coalhopper\def2\wagon\coal_hopper_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\coilsteelcar\def2\wagon\coil_steel_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\coilsteelcar\default\wagon\coil_steel_car.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\covered_hopper\def2\wagon\covered_hopper_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\covered_hopper\default\wagon\covered_hopper.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\doublestackcar\def2\wagon\double_stack_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\refridgeratorcar\def2\wagon\refrigerator_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\refridgeratorcar\default\wagon\refrigerator_car.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\tankcar\def2\wagon\tank_car_def2.bin Default Stock
Kuju\RailSimulatorUS\railvehicles\freight\tankcar\default\wagon\tank_car.bin Default Stock
RSC\GG1Pack01\railvehicles\electric\gg1\prr_dgle\engine\gg1_engine.bin
RSC\HorseshoeCurve\railvehicles\diesel\f7\default\engine\f7a_default.bin
RSC\HorseshoeCurve\railvehicles\diesel\f7\default\engine\f7b_default.bin
RSC\HorseshoeCurve\railvehicles\diesel\gp7\default\engine\gp7_default.bin
RSC\HorseshoeCurve\railvehicles\freight\boxcar_x29\default\boxcar_x29.bin
RSC\HorseshoeCurve\railvehicles\freight\flatcar\default\flatcar_40ft_crates.bin
RSC\HorseshoeCurve\railvehicles\freight\hopper_h21a\default\hopper_h21a.bin
RSC\NorthEastCorridor\railvehicles\electric\aem7\default\engine\aem-7 engine.bin
RSC\NorthEastCorridor\railvehicles\passenger\amfleet\amcafe\amcafe.bin
RSC\NorthEastCorridor\railvehicles\passenger\amfleet\amcoach\amcoach.bin