I tested while disabling all mods that the night light fuel doesnt deplete by itself.
I built a campfire and a night light, fueled up the campfire to max then waited like 10 mins and the campfire was out but the night light was still going with the default building fuel(didnt add any extra nightmarefuel after building it)
Steps to Reproduce
Build a Night Light and wait for it to burn out
This issue has been fixed in either a future version or updated in a previous version.