when water spawns in a world, it can be messed up

when water spawns in minecraft, it's been very glitchy. I've seen it spawn without a source block, continue after a source block was destroyed, and not flow as far as it should. that means that sometimes, when I come upon water that was naturally there, it flowed to a certain point, then, as if there were a sign blocking it, it just falls short of it's flow distance.