My first thought is that if water is sitting so long it has a chance to grow fungus, mildew, or algae, it is not being changed out often enough, or it could simply be that the bowl itself is contaminated and causing it. Any kind of material that is porous can easily get stuff growing down inside where it can be very difficult to clean it properly. Like others suggested, try a new bowl, and clean frequently. Snakes often prefer very fresh water to water that which has been sitting in their bowl for days anyway.
Second, ball pythons hide. That is perfectly normal behavior, they are nocturnal and generally shy... but you mention "cuddling"? Maybe I'm misunderstanding you and jumping the gun, but snakes by-in-large are solitary creatures (with the exceptions of brumation and breeding season) - so should really not be housed together, at all. This could be causing stress, thus causing an inclination to hide more than normal. They're not cuddling, they're competing for the best hiding spot, or the good spot for warmth. Not to mention, all
snakes are opportunistic predators. I have received more than one rescue snake because the owner freaked out after their once cute pet ate his cage mate. Not saying that will happen to your snakes, I've heard of hundreds of cases of snakes being housed together for years without issue, but I can't really see why anyone would want to take that chance.
Another thing to consider is that it is winter. Most of us keep our houses at a pretty constant temperature, but in the winter things naturally cool off a bit, there is less sunlight coming in the windows, and snakes can recognize these changes even if they aren't actually out in the elements. This can be enough for them to decide it is time to brumate (hibernate), and thus hide more than they might when it gets warmer.
It may just be because my snake collection is a rather large one, but I tend to prefer simple and easy when it comes to cage maintenance. If a water bowl is large and heavy to move, and difficult to keep clean, I'd just chuck it out and get something easier to deal with. The simpler the setup, the easier it is to keep clean, the less tinkering you have to do with it, generally the happier the snake.