I ripped out the toilet in the master bath and cut out the sheetrock behind and found 2 shutoffs coming up from the slab. which led to ripping out the lower sheetrock in our kitchen and pulled the hot water heater and cut out the wall in the heater room also. I found hot and cold pipes going thru the kitchen wall behind the cabinets where no sink exists. Long story short used 20 feet of soft copper to run a new hot line from the heater room to the hot shut off I found behind the toilet to bypass the slab hot line.
Water heater back in and no leaks and no continuous cold water filling the water heater.