387.731 Script @NuclearFurnace/control.lua:25: on_configuration_changed: {"used-up-uranium-fuel-cell", "used-up-uranium-fuel-cell"}
450.847 Error MainLoop.cpp:1202: Exception at tick 35536: The mod Bob's classes and multiple characters mod (0.18.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event bobclasses::on_player_toggled_map_editor (ID 116)
bobclasses/control.lua:459: attempt to index field '?' (a nil value)
stack traceback:
bobclasses/control.lua:459: in function 'close_class_gui'
bobclasses/control.lua:419: in function <bobclasses/control.lua:418>

I'm fairly sure I fixed this problem a long time ago (back in 0.17), and I just tried it and it didn't crash for me.

However... look at the first line there, NuclearFurnace/control.lua line 25... that's not my mod.
could it be the other mod doing something?

The crash was about 63 seconds later. The first string comes from my mod, it's small log spam to be sure that all goes right.