Those 2 screws are NEVER installed by Dometic when built. Those screws are supplied when you replace the water inlet valve and you use them when you replace the valve. ALL those screws do is make sure the new valve does not "pop" loose since the original is a plastic catch type system. I would suspect this water valve is defective or has some type of debris in it. But, Dometic has built thousands of these model toilets and that is a new complaint, that I also have never heard of. They sent a new toilet because I assume they want the old back to test it? Or did they just state to throw the old away? Doug