To elaborate

When I was creating an underwater puzzle and completed it, the plan was to have a breathing station like suspending the water with signs, but when I tested it I can't breath in, just like what you can see in the screenshots.

So my guess to the bug was, if the player was diving and after it floats above the water, the game recognizes you are still diving because you are still in water and continues to reduce your respiration, and it will go back to normal if you go back on a land.