Light from engine is present in some situations, when it shouldn't be where.
Confirmed situations are:
Engine has MinThrust set to value more than zero. In this case engine emits light even when it's not started.
Engine was "broken" by Kerbalism (malfunction or critical failure, but without destroying the engine). Broken engine still emits light. It could be true also for other mod, which may "break" engines, but only Kerbalism was tested at the moment.
Images illustrating the problem:
Light from engine is present in some situations, when it shouldn't be where. Confirmed situations are:
The solution could be to implement engine status check in getThrottle() function: https://github.com/linuxgurugamer/EngineLightRelit/blob/master/EngineLightRelit/EngineLightEffect.cs#L124