In thinking about it, when I filled the tank I used a mixture of hot and cold water from the tap...and of course I have copper pipes on the hot water heater
I made a similar mistake using hot tap water. I was cycling my tank, and my cycle just stopped. I do not know if it was from using hot water for sure, but that is the only thing I can think of doing wrong. I do not have copper plumbing in my house, but I was concerned with the metal in the hot water tank.