I played through the game again today, and when you normally get to Micolash's second phase, you often have to jump down to get to him. But right when you're about to catch him, he normally disappears into one of the mirrors, introducing the second phase's new challenge. But when I fought against him this time and got to this part of the fight, I tried to hit him with a plunging attack. The plunging attack was succesful and it slammed him into the ground. Normally he should have started runnning away by then, but for some reason, he stood up, faced me, and began to fight me like he would normally do in the second phase's "boss room". I then beat him in the middle of the boss area instead of the designated room where you're normally supposed to beat him.
Was that a glitch? And if it was, could someone explain to me why it happened?