This message appeared while I was in a train in automatic mode, it was on it's way to a temporary stop, and I adjusted the schedule. I haven't tried to make any tunnels yet.

https://i.imgur.com/QVXe6Hw.png

These are the last few lines of the log:

18473.560 Script @__RoboTank__/control.lua:163: Player character 8 has entered vehicle 41001.
18475.862 Script @__RoboTank__/control.lua:163: Player character 8 has exited a vehicle.
18475.862 Script @__RoboTank__/control.lua:163: pi_controllers is nil?  event.player_index=1 char_pi=-1
18479.077 Script @__RoboTank__/control.lua:163: Player character 8 has entered vehicle 41001.
18494.942 Error MainLoop.cpp:1199: Exception at tick 1467750: The mod Train tunnels caused a non-recoverable error.
Please report this error to the mod author.

Error while running event traintunnels::on_train_changed_state (ID 23)
__traintunnels__/control.lua:1100: bad argument #1 of 5 to 'find' (string expected, got nil)
stack traceback:
    [C]: in function 'find'
    __traintunnels__/control.lua:1100: in function <__traintunnels__/control.lua:1042>

Ok I can reproduce this easily, I have https://mods.factorio.com/mod/beautiful_bridge_railway, cargo ships and honk (and a bunch of other mods that shouldn't affect this): drive the train over a bridge that goes over land as well, with a temporary stop as target - when the train gets to the land it crashes

EDIT: it appears to be solely related to temporary stops, but I've removed the mod because of the crashes and it doesn't even work (some wagons ALWAYS get disconnected, and vehicle grids are always lost when going through a tunnel)