When I first started feeding F/T I used the same hot water method and also experienced a higher rate of exploding preys , since than I have change the way to thaw the preys no longer experience this kind of problem.

Here is what I do, I let the prey thaw at room temp (this also help entice the snake to eat) once thawed, I warm it up with a hair dryer, works great and no more exploding rodents.