So, whenever I add any mod, doesn't matter what it is, my inventory size resets and it drops the "spidertron engineer mk2" and "Spidertron Engineer mk3" items on the ground... it's really annoying. Eventually it fixes itself, but yeah.

Thanks for the report, that's not great! It should reset itself when you get in and out of a vehicle (and on a number of other events). I'll see if I can get a fix for it.

Are you supposed to be able to enter and exit vehicles? it wont let me press enter to do so

I'm having same problem, getting in and out of a train fixes it but still highly annoying.

Would you mind telling me which mod it is? Or a list of mods