Hot water back flowing into main tanks

[blt4spd]

1975 31ft. center bath. Camping in Idaho, just noticed today that I'm getting hot water out of both taps in kitchen and bath. When turning on the water pump is seems to never get to full pressure and shut off. Always had a few issues with the water system but never anything like this. How is the water in the water heater getting back into the main tanks? Any ideas would be helpful. Thanks

[DKB_SATX]

Does your trailer have a bypass valve setup for bypassing the water heater when you winterize the plumbing?

It doesn't sound like hot water is getting into the freshwater tank, it sounds like it's being distributed to the cold-water lines by some cross connection. The most likely thing I can think of are water-heater bypass valves that are halfway between bypassed and on, especially if this hasn't happened before.