I don't think it is a safety issue but just the way the pressure regulator works. I am sure the regulator in Emils system regulates the pressure more accurately than the Mahle filter /regulator but the Mahle one has to comply with it's OEM specification that says it has to hold pressure after supply stops for a time, probably because most engines fire up quicker than the X-wedge if they stall. I imagine it is easier to regulate a constant leak rate than to hold a pressure when the supply is gone, particularly for a combined filter and regulator that is a throw away item built to a price of about £40. Agreed that in our installation there is no need for the system to hold pressure for any length of time but most of these filter/regulators do just that.
