I had the same thing happen to 2010 3400Rl. There is a
vacuum breaker/check valve located in the wall behind your shower controls that has gotten cracked or damaged. I accessed mine by removing the shower controls and reaching into the wall and pulling the pex type tubing through the opening. I did replace mine but I really don't think it's necessary since this line is NOT tied in in any way to your fresh water lines in the rest of the coach. You can get the needed fittings at your local home center to fit the tubing together if you don't want to replace the broken piece. P.M. me if you have any questions and I'll be glad to help. Tim
