As KyNola indicated, your puck won't burn to ashes. The Bradley puck feeding system is designed so that, ideally, the pucks are completely charred, but not burned to ashes.
In our less than ideal, real world, several factors can contribute to less than complete charring of your pucks. A dirty burner plate or pucks that have absorbed moisture are two. Others include not preheating your puck burner before it receives the first puck, cold weather (forum member report less than complete charring during below freezing smokes), some variability in how firmly compressed the chips in the pucks are, and what type of wood the pucks are made from (as I recall, oak, and a couple of other quite hard woods are prone to less than complete char).
I have come to accept that once in while I may get an occasional puck with less than complete char. As long as the pucks are mostly charred, I don't worry about it. It doesn't seem to affect my results.
