The only thing I can suggest, and I am really not sure it would make a difference, is to make sure the hot water bypass valves are in the correct position.
On your water tank, there should be three valves that constitute a winterizing bypass.
There is a valve on the hot water side, on the cold water side, and a crossover valve - physically located between the two other valves.
In the summer, when using the hot water tank, both the hot and cold water valve should be open, and the crossover valve should be closed.
In the winter, during storage, both hot and cold water valves should be closed, and the bypass valve should be open. This effectively removes the hot water tank from the water system and couples the hot and cold water lines together. This is done for expediency in draining and winterizing the system (whether you blow it out or put pink antifreeze in it).
The only thing I can suggest is make sure all three valves are in the correct position.
The only thing that works on a RV is the owner...