Bronze Clockwork Dragon in Bloodbay does not drop any kind of ingots, its completely make sense for him to drop bronze ingots. If you think that bronze ingots drop are bad idea - would be great put back silver ingots to his loot table, but in terms of lore and atmosphere, bronze ingots are the best choice.
Interesting suggestion! Certainly, the clockwork dragons should have mostly the same loot but it would be good to also have some variation. I'll make a note to review their loot at some point. Issue #71791