I am a little concerned that your other ball python likes to soak so much. Ball pythons aren't normally the soaking type and excessive soaking is usually an indication of a bigger problem.
What kind of hides are you using for your snakes?
Also, you need to use a reptile thermostat with a UTH. Even with a glass tank, burns can still happen. This could be the reason why your snake chooses to sit in the water bowl instead of in the hide.
There are other ways to bring up humidity. Insulating the sides and back on the tank with foam core board (on the outside of the tank) can help hold in temps better and maybe eliminate the need for a CHE or lamp, which in turn will raise the humidity.
What substrate are you using? There are certain substrates that can help raise humidity.
Covering 3/4ths of the screen lid with aluminum tape will also help to trap humidity that would otherwise be lost.
A big bowl is not always the answer to keeping humidity up.