I've run into an issue where my netherite pickaxe with Fortune III, Unbreaking III, and Efficiency II, won't yield any extra diamonds or coal. I conducted a small test with a diamond pick and a netherite pick enchanted with Fortune III only, a lined up 32 diamond ore for each pickaxe (64 diamond total). At the end, neither pickaxe yielded no extra diamonds. This is what led me to believe the fortune enchantment is bugged. There could be more but I have not tested for others yet (such as looting).