Connected an inventory sensor to a stack inserter hoping to detect locomotives at a refuelling station. To test, I drove a car in front of it and got the following error immediately:

The mod Inventory Sensor (2.0.4) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Inventory Sensor::on_tick (ID 0)
Filter conflicts with filter in slot 2.
stack traceback:
[C]: in function 'set_slot'
Inventory Sensor/control.lua:511: in function 'UpdateSensor'
Inventory Sensor/control.lua:208: in function <Inventory Sensor/control.lua:184>