Puck sticks to group screen after pull I have a Gaggia Classic and am generally happy with my pulls.  18g of grinds pulls in 20ish seconds give or take.  I have a tamper with a spring and feel I'm fairly consistent overall.  Baratza Encore burr grinder.
One thing I've noticed recently is that the puck is pretty damp after and occasionally sticks to the group screen instead of coming off in the portafilter.
Does this indicate any particular issue I should be aware of?
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.