There is certainly a memory leak in the oil update (game eating up 8 gb of ram+swap after some time) and I think I located at least one possible cause of it.
I noticed that after the game gets all laggy due to leaked memory, opening menus of specific buildings is unbearably slow, even compared to usual lag from memory leaks. I noticed it with pneumatic door (was herding pufts).
Not sure. Select buildings over and over while observing memory usage?