Thank you for answering!
So if the torch or candle shines outside in a scene with an HDRI, is the problem due to (a) an unnatural power setting on the digital torch/candle, (b) over or under exposure on the scene, or (c) both? Or does it just depend?
You say the problem arises when you add light-casting objects to a scene with an HDRI, why is this? Because the candle is suddenly brighter than what it would realistically be in the “daylight” conditions simulated by the HDRI?