I was having issues with headspace between the puck and the shower screen recently with certain coffees and decided to switch from an 18 gram vst basket to a 20 gram. This ended up really improving the quality of my shots. You may want to try reducing your dose a bit to see if that makes a difference. If it does, you can buy some larger baskets if you prefer longer shots.
"Coffee is the lifeblood that fuels the dreams of champions."