Generally, in my experience, Royals are one of those snakes that don't shed well for some reasons or another. By that I mean that they seldom shed in one complete section that is like the proverbial inside out sock.
Humidity does play a part, and keeping the humidity above 60%, ideally 70% around the time of shedding will help, but often the combination of a heavy bodied snake with small scales results in the skin tearing, often leaving bits or strips attached to the top along the spine.
I've kept Royals for 30 years, and noticed that the same individual can have a bad shed on one occasion, but the preceding shed and subsequent sheds were fine and the skin came off the snake without any intervention. In that time nothing had changed in the environment.
In that time I've never experienced any of my royals trying to fit into the water bowl at the time of shedding, and looking back on my records (we all keep records don't we ?) for my adult female, she sheds around 5 times a year, averaging 11 weeks between sheds. In the past 20 sheds, 18 were full, one a partial, and one that needed assistance. On those two occasions a soak in a bath and gentile rub with a damp towel removed the bits still attached. If your snake is spending a lot of time in the water, and your environmental conditions are otherwise OK, then this would indeed suggest that something else is the cause, especially if the snake seems to be in a constant shedding cycle. Mites are the obvious cause, and it would be worth treating the snake and the vivarium for a mite infestation.