Why do I keep getting coffee grounds when it brews?

It could be a couple of things.  The top needle could be dull after many usages and it is pushing down the pod before the needle penetrates the top seal which causes the bottom needle to go too far in the bottom  and  cut into the built in filter in the cup.  Also it could be  defective pods. If you use recycle pods this over time will dull your needle. Hope this helps.