the indentation on the puck from it swelling is normal, and is no cause for worry. Make sure you level off the coffee before tamping, to ensure a uniform puck density.
And most of all, make sure you use fresh coffee. make sure you have a consistent Grind, dose, repeat, and adjust the grind to get the correct flow rate. Make sure you distribute to avoid channeling. But you mus start with fresh coffee. Do you know how old your coffee is?