off-white debris on the washer inlet screens

Getting a new washing machine today. While moving the old one out of the way and removing the water supply lines I noticed that the screens on the back of the washer inlets were covered with an off-white, brittle plastic like substance. I've been recently having water heater issues as well, and after reading up on this now believe that the water heater dip tube is to blame for both of these issues. I first noticed that during a shower the water is warm as usual but after a few short minutes it gets cooler and I have to adjust the water temperature. That leads me to believe that it is a corroded or cracked dip tube as the likely cause. Does this sound right?