When attempting to place the SEQ-3 / SEQ-9 Container Module parts on any vessel, the part model and attach nodes disappear. Looking into the console the following error appears, seems to be related to the simulator:

[LOG 04:28:28.818] KerbalEngineer -> Exception SimManager.StartSimulation() // System.NullReferenceException
at (wrapper managed-to-native) UnityEngine.Component.get_transform(UnityEngine.Component)
at KerbalEngineer.VesselSimulator.PartSim.New (Part p, System.Int32 id, System.Double atmosphere, KerbalEngineer.LogMsg log) [0x00012] in <134deb60e87843589b7ea1a020650b28>:0
at KerbalEngineer.VesselSimulator.Simulation.PrepareSimulation (KerbalEngineer.LogMsg _log, System.Collections.Generic.List1[T] parts, System.Double theGravity, System.Double theAtmosphere, System.Double theMach, System.Boolean dumpTree, System.Boolean vectoredThrust, System.Boolean fullThrust) [0x00185] in <134deb60e87843589b7ea1a020650b28>:0 at KerbalEngineer.VesselSimulator.SimManager.StartSimulation () [0x000ba] in <134deb60e87843589b7ea1a020650b28>:0 [LOG 04:28:28.819] KerbalEngineer -> at (wrapper managed-to-native) UnityEngine.Component.get_transform(UnityEngine.Component) at KerbalEngineer.VesselSimulator.PartSim.New (Part p, System.Int32 id, System.Double atmosphere, KerbalEngineer.LogMsg log) [0x00012] in <134deb60e87843589b7ea1a020650b28>:0 at KerbalEngineer.VesselSimulator.Simulation.PrepareSimulation (KerbalEngineer.LogMsg _log, System.Collections.Generic.List1[T] parts, System.Double theGravity, System.Double theAtmosphere, System.Double theMach, System.Boolean dumpTree, System.Boolean vectoredThrust, System.Boolean fullThrust) [0x00185] in <134deb60e87843589b7ea1a020650b28>:0
at KerbalEngineer.VesselSimulator.SimManager.StartSimulation () [0x000ba] in <134deb60e87843589b7ea1a020650b28>:0

Game Version: 1.12.1.3142, MH and BG DLCs
Modlist below, may be an issue regarding its interaction with FAR?

Airplane Plus (AirplanePlus 26.5)
AT Utils (AT-Utils v1.9.6)
AtmosphereAutopilot (Fly-By-Wire) (AtmosphereAutopilot v1.5.16)
Aviation Lights (AviationLights 1:v4.1.2)
B9 Aerospace Procedural Wings - Fork (B9-PWings-Fork 3:0.43.0.8)
B9 Part Switch (B9PartSwitch v2.18.0)
Basic Procedural Textures (BasicProceduralTextures v1.2)
BD Armory Continued (BDArmoryContinued 1:v1.3.4)
Breaking Ground (BreakingGround-DLC 1.7.0)
ClickThrough Blocker (ClickThroughBlocker 1:0.1.10.16)
Community Resource Pack (CommunityResourcePack 1.4.2)
Deployable Engines Plugin (DeployableEngines 1.3.0)
Distant Object Enhancement Continued (DistantObject v2.0.2.0)
Distant Object Enhancement Continued default config (DistantObject-default v2.0.2.0)
Environmental Visual Enhancements Redux (EnvironmentalVisualEnhancements 3:1.11.3.1)
Ferram Aerospace Research Continued (FerramAerospaceResearchContinued 3:0.16.0.3)
Firespitter Core (FirespitterCore v7.17)
Firespitter Resources config (FirespitterResourcesConfig v7.17)
HullcamVDS Continued (HullcamVDSContinued 0.2.1.1)
Kerbal Actuators (KerbalActuators v1.8.3)
Kerbal Engineer Redux (KerbalEngineerRedux 1.1.9.0)
Kerbal NRAP - Procedural Test Weights (KerbalNRAP 1.6.0)
KSP Recall (KSP-Recall v0.2.0.1)
Making History (MakingHistory-DLC 1.12.0)
Mark IV Spaceplane System (MarkIVSpaceplaneSystem 3.2.0)
MechJeb 2 (MechJeb2 2.12.0.0)
Mk1-Cabin-Hatch (Mk1CabinHatch 1.0.1)
Mk2 Stockalike Expansion (Mk2Expansion 2:1.9)
Mk3 Stockalike Expansion (Mk3Expansion 1.6)
ModularFlightIntegrator (ModularFlightIntegrator 1.2.10.0)
Module Manager (ModuleManager 4.1.4)
Near Future IVA Props (NearFutureProps 1:0.6.5)
Near Future Solar (NearFutureSolar 1.3.1)
Near Future Solar Core (NearFutureSolar-Core 1.3.1)
Physics Range Extender (PhysicsRangeExtender 1.20.0)
Procedural Parts (ProceduralParts v2.1.2)
Procedural Parts - Ven's Revamp Style Textures (VensStylePPTextures 1.1)
RasterPropMonitor (RasterPropMonitor 1:v0.31.4)
RasterPropMonitor Core (RasterPropMonitor-Core 1:v0.31.4)
RCS Build Aid (RCSBuildAid v1.0.6)
Real Plume (RealPlume 2:v13.3.2)
Real Plume - Stock Configs (RealPlume-StockConfigs v4.0.8)
SCANsat (SCANsat v20.4)
scatterer (Scatterer 3:v0.0772)
Scatterer Default Config (Scatterer-config 3:v0.0772)
Scatterer Sunflare (Scatterer-sunflare 3:v0.0772)
SmokeScreen - Extended FX Plugin (SmokeScreen 2.8.14.0)
Stock Visual Enhancements (StockVisualEnhancements 3:v1.4.1)
Stock Visual Enhancements-High Res Textures (SVE-HighResolution 3:1.0.8)
Stock Waterfall Effects (StockWaterfallEffects 0.5.1)
Throttle Controlled Avionics (ThrottleControlledAvionics v3.7.2)
Toolbar (Toolbar 1:1.8.0.5)
Toolbar Controller (ToolbarController 1:0.1.9.4)
Trajectories (Trajectories v2.4.1)
TweakScale - Rescale Everything! (TweakScale v2.4.5.1)
Waterfall Core (Waterfall 0.6.6)
Zero MiniAVC (ZeroMiniAVC 1:1.1.0.1)