Air needed to go up the chimney when there was heat in the box. It was easier to take air in from the gaps than it was to draw it through some chambers and passageways, through the fire and log jam, and into the flue. Enough got in to keep some heat going, but it wasn’t getting the air it needed from where it needed it. If it’s been like that for a while, you might have to re-learn the stove’s attitude. It should run hotter now.There was and it is snug in place now. It was free floating before.