I got the following error with Krastorio 2 while placing a burner mining drill
Notice

The mod Module Party (1.0.5) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Module-Party :: on_built_entity (ID 6)
Unknown item name: kr-ai-core-module
stack traceback:
[C]: in function 'insert'
Module-Party /control.lua:59: in function < Module-Party __ /control.lua:56>

Tracking. I'll look at the k2 mod and see what I can do.

I am unable to reproduce your game crash; I can place machines and they populate with random modules as intended without any game crashes (I pinged you in the Factorio discord w/ a scrnshot). Searching through K2, there are no modifications to the 'module-category' prototype that would add a 'kr-ai-core-module' item into the game. You have some other 3rd mod interfering with K2 + Module Party.
To note as well, K2 does not officially support Space Age as a dependency, while Module Party requires it. As K2 says, it shouldn't crash the game (and it doesn't for me), but because of that they might be fundamentally incompatible.

I was able to isolate the crash, it is Krastorio 2 Spaced Out + Moshine + Module Party, it crash with different unknown item names:
kr-ai-core-module, kr-ai-core-module-2 and kr-ai-core-module-3
The crash it not garanteed in every entity you place if you don't iterate the list enough to reach a crashing module it doesnt happen (probably). It didn't crash when it added a rare prod 1.

You need the 3 mods active at the same time, the crash seems to be caused by this line.
https://github.com/Polka37/Krastorio2-spaced-out/blob/main/prototypes/compatibility/planets/moshine.lua#L59
together with module party.

It always crash on the first or second machine you place.

Game crashes fixed. Currently, Moshine buildings that only use the "ai-speed" module category will have no random modules placed in them (dataextractor, dataprocessor, supercomputer). I believe it's intended in Moshine for you to automatically craft and insert these into machines anyway, so I think this is an acceptable trade-off. Just be sure to keep the ai-speed modules outside of your player inventory if you change out the modules (you can use the logistic bots for this too since modules aren't deleted due to API limitations in this case).