I immerse my soap in the bowl in hot water for about a minute before I shave. This helps in getting the lather more hot than just using the brush dipped in hot water. When I am done , I drain all the water from the soap and bowl and let it air dry.
Never had an issue with it myself. Sure, the water dissolves some soap but it's a trace amount.
As usual -- go with what works for you.
My soap has never turned into shaving cream.