I got the duty „defeat 7 Mini-Bosses anywhere“ and I played two repeatable quests and one exploration (level 21 in Hooligan Timberlands) and after that I were at 3/7 Mini-Bosses.
And there is my question: level 21 contained 3 Skullcrowns and 1 Torch and I‘m very sure that Torch was counted as Mini-Boss (if not there might be a bug that Mini-Bosses from exploration are not counted?). But the Skullcrowns were not counted, even though they had (what I call it) a „big spirit bar“. I thought that I recognize Mini-Bosses through this bar but that seems not to be true or there are several stages of the „bigness“ of the spirit bar. So how do I know which dragon is a Mini-Boss?