Hey Konstantin,
the error arises from the initial state specification for the simulations B and C. Johannes opened an issue on Github related to that topic and we will work on that.
To get your model working, you can not use capital letters for that. It needs to be:
# Simulation B
model.root.input.model.unit_001.init_state= stateAfterA
# Simulation C
model.root.input.model.unit_001.init_state = stateAfterB
For more information, see also here.