The game seems to crash after about an in-game month or so every time I play it normally with multithreading enabled. When I turn it off the game does not crash.

I originally suspected it may have to do with the suspended water wheel constructions and the seasons changing to winter, but it seems to crash even before that in some of my tests.
If it helps, I am at this stage doing the following things:

• building a chained screw pump system to generate mist in a statue garden
• queuing up many fortress visitors to be interrogated as there seems to be no shortage of conspirators coming to visit (hooray)

I am not certain what is specifically causing the crash but it does not seem solely related to the "projects" listed above. I have managed to get further along in my game after avoiding the crash (simply by turning off multithreading and playing normally).