I have a La Pavoni Stradivari that allows water into the grouphead when the lever is raised, but does press the water through when the lever is pushed down. Bizarrely, there is no resistance when the lever is pushed down and no water makes it through the puck. It sounds as if water continuously is let into the grouphead even when the lever is pushed back down. I have used to machine without issue for 6 months and the issue came on very suddenly. Has anybody had a similar issue? Thanks!