So I've been facing this problem for a while now and it seems I'm the only one who's actually having a problem with it at the moment.
So I'll run my city for a good 5-15 years then "Invalid IL code in DifficultyMod.WBBResidentialBuildingAI2:SimulationStepActive (uint16,Building" Strikes. I've actually fixed this before by simply by destroying buildings in-game and seeing if the error message gose away. But now it seems Impossible that it could simply be one building as the city's been developed 15 years and every possible residental building has already been built prior to the bug. Is there a simpler way to locating the asset that's creating this issue and/or letting the bug itself slide. The bug isn't causing any problems ingame but the notification of the bug is what's preventing me from actually enjoy it too much.