no leaks but same problem with fast sloppy extractions. Bezzera said"- the flow rate without the filterholder (at least 250/300 cc/min)" the flow rate on my machine is about 500cc/min so I'm getting twice the norm. Now just to figure out why. I asked Bezzera this question, waiting for the answer.
Did you ever figure out what the brew pressure is? It almost sounds like the OPV may have picked up a little scale or something resulting in a significant jump in pressure. A bad gicleur (brew flow orifice) will allow too much flow, but having it happen overight doesn't sound right. Mike