they will do the things you experienced if not installed correctly. There is a small pinhole fitting installed at the top of the vent loop on the intake to both prevent syphoning and allow the vacuum in the bowl to leak down. You should be able to lift the lid again in about 7-10 seconds. The maintenance instructions say to keep this clear of salt etc., I have never had to do anything with them. Perhaps the charter company did not install it. Shooting water onto the lid will also happen if you do not install the pump upright (as it states in the instructions). I did not follow that on one of mine, and it did exactly that (this is because the check valve in the pump does not work efficiently sideways).

So install them right (and you must have the room to be able to do this) or use something else. The pump should be upright or within 45 deg of upright, and should be positioned slightly above the rim of the bowl. Too high and there will be too much drainback after use, leaving the bowl more full that you would like.