"Stuck" on loading screen after using Konstructor

[modus]

Ok guys, so I have a problem after using the Konstructor from the super awesome mod Konstruction. "So why don't you ask over there?", I hear you screaming at your screen. First of all, chill. Second, I'm not really sure Konstruction actually is the problem.

So here goes.

First, some formalities. Here's my mod list

Spoiler

000_AT_Utils
000_ClickThroughBlocker
000_Harmony
000_USITools
001_ToolbarControl
AlarmEnhancements
B9PartSwitch
Benjee10_MMSEV
Benjee10_sharedAssets
Benjee10_stowaway
BoulderCo
CommunityCategoryKit
CommunityResourcePack
CommunityTechTree
ConfigurableContainers
ContractConfigurator
CryoEngines
CryoTanks
CTTP
CustomBarnKit
DecouplerShroud
DeployableEngines
DistantObject
DMagicOrbitalScience
DynamicBatteryStorage
EnvironmentalVisualEnhancements
FinalFrontier.dat
Firespitter
FruitKocktail
HabTechProps
HeatControl
JX2Antenna
KerbalAtomics
KerbalEngineer
KerbalReusabilityExpansion
Kopernicus
KSPCommunityFixes
MarkIVSystem
MiniSampleReturnCapsule
ModularFlightIntegrator
ModuleManager.4.2.1.dll
ModuleManager.ConfigCache
ModuleManager.ConfigSHA
ModuleManager.Physics
ModuleManager.TechTree
MPE
NavyFish
NearFutureConstruction
NearFutureElectrical
NearFutureExploration
NearFutureLaunchVehicles
NearFutureProps
NearFuturePropulsion
NearFutureSolar
NearFutureSpacecraft
Nereid
OPM
OrbitalLFOEngines
PlanetShine
ProbesBeforeCrew
RandomMainMenuBodies
ScienceAlert
Squad
SquadExpansion
StationPartsExpansionRedux
STMRibbons
StockWaterfallEffects
SystemHeat
SystemHeatConverters
SystemHeatFissionEngines
SystemHeatFissionReactors
SystemHeatHarvesters
TarsierSpaceTech
TrackingStationEvolved
TriggerTech
UmbraSpaceIndustries
Waterfall
WildBlueIndustries
XenonHallThrusters

and here are my log files for my 1.12.3 install: KSP log en player log

I thought I saw someone reporting something similar after the latest version of Konstruction (and the other USI mods) dropped, but I can't find it anywhere. So either my searching skillz suck, or I only dreamt it. Probably the second.
I thought the (imaginary?) report said that Konstructing a vessel that had one or more Hab modules (so a MKS part or a part from another mod using a MKS patch) caused problems.

When I tried exactly that, I had troubles indeed: building the 'Mun Hab Pilgrim2' (with parts from both SSPXr and Planetside Exploration Technologies, both 'enriched' by MKS) through the 'Konstructor' (the orbital shipyard from Konstruction) caused an infinite loading screen.
Game stuck? Well, not really, because my KAC window was still available, and I could switch to another ship via that way. When I went to the map screen, I could see that the 'Mun Hab Pilgrim2' actually was build. When I tried to switch to it, I got a never ending loading screen again, so I had to escape using KAC again.
I could switch to the Konstructor, however, and then use the 'swith to nearby vessel' key. Oh boy. The vessel instantly turned into spaghetti, back into a ball, stretched again, ...went into a rapid spin and acceleration, ...Total Mess.

So was it the hab modules? Maybe, because the Konstructor works just fine when building other craft without hab modules. I can also build and load the 'Mun Hab Pilgrim2' from the VAB*.
So it's got to be Konstruction right? Well, when I reverted to the previous version (the bleeding edge from October 2021), it did not solve the problem.
Maybe another USI Mod (like MKS)? I reverted the whole USI suite, did not solve it.

Looking at the logs, I see weird stuff (*like FlowGraph errors from the vessel I loaded from the VAB?), but examining logs isn't my strong side. So I turn to you, logfile nerds connaisseurs.
Do you guys have any clue?
The log files are from a session where I started KSP, switched to the Konstructor (time warped a bit), Konstructed the vessel, looked at the loading screen a bit, switched to another vessel, and closed to game.

Anyway, it's not like my save (using it since 1.7!) is completely broken, everything works fine except Konstructing Hab modules, but an answer would be nice.

Cheers!