building with anything from the station parts expansion pack causes instant and indiscriminate destruction. as well as particularly large parts i.e. mobile processing lab

What is this pack? Is at a mod? Does it work good in your game with the stock parts?

the pack is a mod that adds station parts. The mod does work with some other modded parts. I have tested smaller ones from USI, but i cannot attach larger vanilla parts such as the mobile processing lab without everything exploding. I can confirm that this issue is not caused by kerbal joint reinforcement as the outcomes of the tests are the same regardless of if that mod (which increases the rigidity of crafts) is installed

It seems to be a mods conflict. I can take a look if you make a simple test on a pristine game (only KIS and the mod in question installed). I would need a to know the exact part name you've been attaching, and I'll need the logs. A short video would help too.