When an entity dies to fire caused by the fire aspect or flame enchantment, the kill is not attributed to the attacker (such as when using arrows) which is clearly visible in the death messages as it doesn't credit the attacker ("steve burned to death", etc). This causes the looting enchantment to not apply, therefore reducing the amount of drops received to the default value used for cases with no looting at all.

Expected result after fix: looting enchantment applies to mobs that die to fire aspect or flame from a player's sword or bow respectively. Also potentially enabling death messages to credit the attacker, such as: "steve was incinerated by alex" or similar.