I think it's normal. They assume that you're going to fill the fresh water tank from a faucet before you leave or from another source with a pressurized fill. You could cut a fresh water hose short and use a pump to get it into the tank. Not a lot of fun, but if you're boondocking, but you could use a hand pump like they use to pump antifreeze into the system.
2015 Dynamax REV 24TB class C