Past a certain point in Bone Keep, none of the torches or orbs are valid targets for Fire Bolt or, in the case of orbs, other cantrips that should be able to target them.
Also, in the fight with the vampire chick and at least one other shortly before it, there were a couple instances where enemies right next to my cleric, with Light cast on his mace, were still unlit. This seems to sometimes happen when the adjacency is diagonal instead of horizontal or vertical. (They were not inside the clouds of darkness that end up all over the place during that fight.) If my mace is close enough to physically hit an enemy's face, they should be well within the light from it.
(I am one of those who thinks the whole lighting system is ill-advised. It's not intuitive or realistic and it certainly isn't in accordance with 5E rules. But if you're going to have it, it really needs some common-sensical QOL tweaks.)