title_body: Puck sticks to group screen after pull
upvoted_answer: Reduce your dose. Having your puck stick to the brew head means the grounds are in contact with the brew head. If you reduce your dose by 1-2g the surface should be low enough as to avoid direct contact with the brew head. Depending on your brew head you might even get channeling if the surface is too high - immediately below the holes where water comes out it might dig a channel into your puck. If you can see dots on your puck after taking it out, it's probably channeling.
  A wet puck in general also suggest too much coffee or too fine of a grind, check out this life hack from James Hoffmann, where he suggests letting the espresso run for a little longer so you can knock it out of the portafilter more easily.