What happened while I was smoking Hookah today?

Odds are it's a combination of 3 things. First when you truly inhale your lungs absorb some of the smoke. So it will always come out less if you truly inhale. Second probably wasn't much coal on the bowl which means you didn't inhale much. Thirdly, when stopped to answer you probably weren't finished inhaling and it there was smoke just sitting in your airways waiting for a good push either way.